I'm mad about linux distros again today and I think I am realizing why this is so hard for me to write about systemically: I have a software engineer brain and so I try to model the various problems as technical problems. And there are numerous technical problems to think about (platform interfaces, ABI boundaries, release management, etc) but the core problem is a social one, which requires a social solution.
In short, all the volunteer-based distributions need to have a gigantic conference where they all come together and *agree to stop working on about 99% of them*, to pool efforts to make a real Linux platform. A lot of people will need to put their egos aside and decide to acquiesce to solutions they believe to be technically inferior, in order to be able to address the diffusion of labor into pointlessly recreating basically the same toolchain a thousand times.
This is a big problem because labor is not fungible and the reason that a lot of these people got involved in distro development *in the first place* is that those sorts of problems and systems are interesting and engaging for them to work on. They all want to have control over a packaging tool, or a build farm, or whatever. The redundancy is a huge problem and a huge waste but it's also the engine that powers the whole thing, to some extent.
Fixing the problem involves driving a truck through that load-bearing "to some extent". Doing a big ugly multi-party negotiation to figure out how we can EOL Qt, to replace it with Gtk everywhere, and get all the Gtk devs on board with being *extremely* nice to the Qt people as we sunset their work. (Did you feel a little thrill because I picked Gtk instead of Qt? Well, I flipped a coin. Imagine I said Qt wins instead of Gtk. You're gonna be that mad about *big* parts of this, no matter what.)

@glyph I mean, yes, but should I write my Windows app to use GDI, GDI+, WinForms, WPF, UWP, or whatever they're doing nowadays?

That only works on the corporate side because they throw oodles of money at propping up that hodgepodge of manager-getting-promotion frameworks, but yeah... that doesn't work so well when volunteer labor is fungible. Imitating corporate dysfunction without corporate resources is... suboptimal.

@xgranade on Linux this stuff matters because the user might be making choices about which ones are available. your package might arrive on a system without GTK, or without configuration for GTK. arguably on Windows making this choice is still a drain on your time and resources, but whichever choice you make the app still *works* and Microsoft has cleverly conditioned their user base to not care at all about how anything looks by using 15 different toolkits internally
@xgranade but, less tongue-in-cheek; it is *about* as miserable to develop for Windows as it is to develop for Linux, the difference is that developing for Windows gets you 7000% as many users so the time investment seems bad. it's a lot more pleasant to develop for macOS (only *3* first-party frameworks now, Cocoa, Catalyst, or SwiftUI! Way less than Linux or Windows, that's apparently the metric!🙃) and it's still 1200% more users, so you keep a similar ratio

@xgranade although wow hats off to "Unknown", the real breakout star of the war for desktop OS marketshare https://gs.statcounter.com/os-market-share/desktop/worldwide/

are a lot of people running the QNX desktop now, or

Desktop Operating System Market Share Worldwide | Statcounter Global Stats

This graph shows the market share of desktop operating systems worldwide based on over 5 billion monthly page views.

StatCounter Global Stats