I haven't been the biggest fan of flatpak and generally wish software would either be packaged as an rpm or an AppImage, but the OP makes a pretty strong case for why it's a good idea (because existing options are too niche, and have no ability to incentivize developers who need to get paid for their work. This leads to Linux desktop having far fewer applications available to them compared to windows and mac.)
I do hope the command-line UX around flatpaks (installing, updating, etc) improves a lot though as currently it leaves much to be desired.