Agreed. This is I think the single biggest contributor to my now fairly radical approach to software. Unless the app is at least source available, I will only use it if I really need it. One of the most valuable things about open source to me now is simply that nobody can take it away. Sure maintainers can disappear, but (aside from accreted cruft/bitrot) I can keep using whatever version as long as I have hardware to run it on.

I dedicated four hours to learning GIMP a few years ago, and many times now I've been so glad I did. There are a ton of books and courses out there for people looking to do the same. Kdenlive is another one I'm super glad I took the time to learn.