Richard Stallman listed four freedoms essential to software users: freedom to run a program for any purpose, freedom to study the mechanics of the program and modify it, freedom to redistribute copies, and freedom to improve and change modified versions for public use. To implement these freedoms, users needed full access to the source code. To ensure code remained free and provide it to the public, Stallman created the GNU General Public License (GPL), which allowed software and the future generations of code derived from it to remain free for public use.

https://en.wikipedia.org/wiki/The_Free_Software_Definition

In my words: It gives back control to the consumer. Instead of the big corporations effectly being in control of your computer, smartphone, the internet platforms, what videos you get to see. And which updates from your friend's will result in a notification and which of your friends to drop. And they'll happily sell your personal data, track you, show massive amounts of advertisements to you and program their software so you get manimpuated into staying longer than you would have wanted on their platform and manipulate you into buying and doing what they like. The Free Software movement is trying to give control back to you, so you can't be exploited.

There are ways to combine free software with making money. For example by selling additional services, consulting and maintenance. There are more and it's a complicated topic.

And there are other challenges. For example our way of using technology today, mainly 'the cloud' makes things even more complicated.