Honestly, the real hurdle now seems to be the support for paid apps. It's such a taboo in the Linux world, for some reason [1], but thankfully Flatpak and Flathub are working towards that goal [2], which ElementaryOS already explored.
I want small, high quality apps like macOS has. I want to make a living building open source software that can be supported and bought commercially—no, donations and sponsoring isn't good enough. I want companies being able to sell their software on Linux through the integrated app store, now that it's finally become good enough.
1: Plenty Linux users think FOSS means never having to pay for software, or that commercial software will kill us all and it's morally wrong. I strongly disagree.
It's "supported" just fine now. You certainly don't need some centralized app store or weird quasi-distro. As you say, it's 100% a cultural problem. No amount of technical effort will change that Linux users expect their software to be open source, and that in practice you cannot sell open source software.
