"forget people who want to make money, nevertheless the fact the devs lets you use the entire program for free anyway!"
At no point did I imply the devs of Reaper are doing anything wrong.
I'm just pointing out that if you're going to pay for something, you might as well see if you can find a similar tool that does what you want for free.
And I've always been annoyed when programs give you popups asking you to pay for something or to rate it on whatever store it came from, etc.
I usually try to avoid programs that do that, and it's usually super easy, because there's almost always an open source alternative.
Like, the example you gave is WinRAR. Who would use WinRAR when 7-Zip exists?