Maybe can add Firefox OS (*) and sailfishOS as well to the list.
Good shot on mentioning all those. Also agree they're not giving credit where credit is due. The last mock-up where you see convergence of smartphone plus PC is invented by Ubuntu Phone and innovated (applied in a relatively large product) by Microsoft with a Lumia (IIRC 950?).
Windows Phone just got (pretty much) discontinued even though Microsoft poured billions into that. Why discontinued? Not enough apps! Maemo/MeeGo had the same issue. Even though browser is most important... no WhatsApp? No banking app? No Spotify? No Netflix? No games? Forget it.
At this point of the game you need a very good Android emulator, native apps, or actually both. I'm aware of two Android emulators: BlueStacks, for desktops really, and the one in sailfishOS (emulates 4.4.x). I doubt Netflix, for example, is gonna run on either since it won't run on rooted Android devices.
Of course the project also has its upsides (see their comparison chart). This is just going to be a massive downside. After the initial happiness, it will be apparent, and a community can fix only so much. The end result is a crippled phone with worse software than Windows Phone or sailfishOS. That might change in the long-term! Who knows.
FairphoneOS and FP2 have their fair share of upsides and downsides but lack of software isn't one of them.
To end with a positive note, maybe the Librem 5 can do it a lot better in the software updates dept. than the average Android vendor
(*) WTB OS-wide uBlock!