Not OP, but a good example would be the various PDF conversion apps around. The freemium/shareware ones all suck in one way or another unless you pay (arbitrary page limits, watermarks etc), the web-based ones make batch processing very hard and have privacy issues. Meanwhile ghostscript, pdftk, imagemagick and co. just work and will continue to work for a long time. On mobile I can use these over SSH on a remote Linux box. LaTeX or LibreOffice vs. Word is a similar example, although you can't always get around using Word.

Or Photoshop, when Adobe switched to a subscription service. I use it maybe 3 times a year, a (legal) old version would be fine but you can't buy one. GIMP it is, even though it has less features.

I want to spend less time looking for new apps/services just because the previous ones went out of business or now charge monthly for 5 lines of code. Libre/Free software mostly stays around, even the unmaintained stuff is often forked/fixed/updated by someone if the fix is small enough.