Given the amount of dependency bullshit I've had to deal with over the years, I'm glad the idea of using shared libraries for everything is dying. I like the core idea of it, but the implementation has never actually Just™ Worked™ in my experience outside of either trivial or curated examples. I guess all those mature applications discovered the same thing.

Flatpacks are great. I've barely ever had a problem with them, and the problems I did have were solvable with a cursory web search. Yes, they take up more space. That's a worthwhile trade-off in exchange for actually working.