I have found that people are generally aware of the scripture in Matthew 24 referring to “love growing cold”.

Here is a large sampling of this verse in various translations:
New International Version
Because of the increase of wickedness, the love of most will grow cold,
New Living Translation
Sin will be rampant everywhere, and the love of many will grow cold.
English Standard Version
And because lawlessness will be increased, the love of many will grow cold.
Berean Study Bible
Because of the multiplication of wickedness, the love of most will grow cold.
Berean Literal Bible
And because lawlessness is to be multiplied, the love of the many will grow cold.
New American Standard Bible
“Because lawlessness is increased, most people’s love will grow cold.
New King James Version
And because lawlessness will abound, the love of many will grow cold.
King James Bible
And because iniquity shall abound, the love of many shall wax cold.
Christian Standard Bible
Because lawlessness will multiply, the love of many will grow cold.
Contemporary English Version
Evil will spread and cause many people to stop loving others.
Good News Translation
Such will be the spread of evil that many people’s love will grow cold.
Holman Christian Standard Bible
Because lawlessness will multiply, the love of many will grow cold.
International Standard Version
and because lawlessness will increase, the love of many people will grow cold.
NET Bible
and because lawlessness will increase so much, the love of many will grow cold.
New Heart English Bible
And because lawlessness is multiplied, the love of many will grow cold.
Aramaic Bible in Plain English
And because of the abundance of evil, the love of many will grow cold.
GOD’S WORD® Translation
And because there will be more and more lawlessness, most people’s love will grow cold.
New American Standard 1977
“And because lawlessness is increased, most people’s love will grow cold.

Jubilee Bible 2000
And because lawlessness shall abound, the charity of many shall wax cold.
King James 2000 Bible
And because iniquity shall abound, the love of many shall grow cold.
American King James Version
And because iniquity shall abound, the love of many shall wax cold.
American Standard Version
And because iniquity shall be multiplied, the love of the many shall wax cold.
Douay-Rheims Bible
And because iniquity hath abounded, the charity of many shall grow cold.
Darby Bible Translation
and because lawlessness shall prevail, the love of the most shall grow cold;
English Revised Version
And because iniquity shall be multiplied, the love of the many shall wax cold.
Webster’s Bible Translation
And because iniquity will abound, the love of many will become cold.
Weymouth New Testament
and because of the prevalent disregard of God’s law the love of the great majority will grow cold;
World English Bible
Because iniquity will be multiplied, the love of many will grow cold.
Young’s Literal Translation
and because of the abounding of the lawlessness, the love of the many shall become cold

I spent 30 plus years in mainstream Christianity being taught that this verse referred to evil or wickedness (typically from the NIV in churches we attended).
I was taught that people would become or are becoming more wicked or evil, and that it would result in love growing cold.
I was always taught this referred to how people treat one another.
When we look at a large sampling of translations, we find that only two use the term wickedness, and another two use the term evil.

What about all the others?
We get 23 versions referring to the law of the bible, either as law, or as sin/iniquity which is a transgression of the law:
1John 3:4
Everyone doing sin also does lawlessness, and sin is lawlessness.

wickedness – 1-2
evil – 1-2
sin rampant -1
lawlessness – 1-2-3-4-5-6-7-8-9-10-11-12-13-14
Iniquity – 1-2-3-4-5-6-7
Disregard the law – 1

If we believe what the scripture is saying, we can assume that not obeying the law of God results in people treating one another badly.
While this is true, we do not need to make assumptions.
Let’s take a look at Matthew 24:11, and we’ll find out what causes lawlessness to abound and love to grow cold:

Matthew 24:11
“And many false prophets shall rise up and lead many astray.”

False prophets.
Leading people astray.
Astray from what?
The instructions of Yehova.
The law.
The Torah.

Here it is altogether:
“And many false prophets shall rise up and lead many astray. And because of the increase in lawlessness, the love of many shall become cold.”
And that is not the end of this concept.
Yeshua Messiah goes further in verse 13:
“But he who shall have endured to the end shall be saved.”

Endure what until the end?
Not being led astray by false prophets.
Not increasing lawlessness.
Not allowing our love to grow cold as a result.
This is what we are to endure until the end.
And what is the reward?
Being saved.
These three simple sentences by Yeshua Messiah tell us that we are saved by not listening to false prophets that result in lawlessness.
And let’s not forget that Yeshua Messiah associates this concept with love growing cold.

Let’s look at three other direct quotes of Yeshua Messiah:
John 14:15
“If you love Me, you shall keep My commands.”
John 14:21
“He who keeps My commands and guards them, it is he who loves Me. And he who loves Me shall be loved by My Father, and I shall love him and manifest Myself to him.”
John 15:10
“If you keep My commands, you shall stay in My love even as I have guarded My Father’s commands and stay in His love.”

Yeshua says that if we love Him we will keep the commandments, the law, the Torah.
In Matthew, Yeshua associates disobedience and lawlessness with a lack of love.
The three quotes from John tell us that disobedience results in a lack of love for Messiah.
I believe this is what Messiah is referring to in Matthew 24.
A lack of love for Him.
A lack of love for Jesus, Yeshua Messiah, proven by the disobedience and lawlessness of men and women. 
In Matthew 24, Yeshua is talking about whether or not our love for Him grows cold.
Are there any other scriptures that would confirm this?
Yes, there are…
Another direct quote of Messiah:
Matthew 7:21-23
“Not everyone who says to Me, ‘Master, Master,’ shall enter into the reign of the heavens, but he who is doing the will of My Father in the heavens. Many shall say to Me in that day, ‘Master, Master, have we not prophesied in Your Name, and cast out demons in Your Name, and done many mighty works in Your Name?’ And then I shall declare to them, ‘I never knew you, depart from Me, you who work lawlessness!’”

Messiah does not know people who live their lives in lawlessness, saying the law is done away with…

We see a test in 1John 2 to find out whether or not we know Yeshua Messiah:
And by this we know that we know Him, if we guard His commands. The one who says, “I know Him,” and does not guard His commands, is a liar, and the truth is not in him. But whoever guards His Word, truly the love of Elohim has been perfected in him. By this we know that we are in Him. The one who says he stays in Him ought himself also to walk, even as He walked.

Anyone who claims to know Jesus, but does not keep the commands is a liar and they have no truth.
Not my idea, but simply what scripture tells us.
Is this a new idea?
Nope.
This concept goes back to the beginning.
God the Father tells us the same thing:
Deuteronomy 13:3-4
“…for יהוה your Elohim is testing you to know whether you love יהוה your Elohim with all your heart and with all your being. Walk after יהוה your Elohim and fear Him, and guard His commands and obey His voice, and serve Him and cling to Him.”
We are being tested to see if we love God.
What are the pass fail criteria?
Guard/keep His commands
Obey His Voice

No, this is not a new concept.
The standard for loving Yehova and Yeshua Messiah (God and Jesus) has been the same since the beginning.
Obedience.
Listen to them.
Know their Voice (the things They say).
Obey them.

False prophets who teach the law is done away with lead people astray, encouraging them to disobey, resulting in love growing cold.
Love for Messiah.
And love for God our Creator.