Indeed. And what many seem to fail to notice is that at it's core it's
exactly the same mistake being made all over again. A mistake that I've seen so many times over and over again, increasingly commonly in recent years, which can be summed up thusly:
"I want to make some incompatible changes in my thing that is being widely used by (say) thousands or millions of people. I could spend a bunch of time ensuring I'm backwards compatible as much as possible, or doing a compatibility layer which would make the transition seamless for most, but that's not sexy work, and it would be something I would have to maintain (also not sexy), and it would take me (let's say) 1000 hours to do. Instead, I'll just insist that each and every one of those thousands/millions of people put (say) 100 hours each into adapting to what I want to do"
It's disrespectful of your users. It devalues their time. It says that your (say) 1000 hours is more valuable than (say) a million people putting in (say) 100 hours each. And it's inefficient - wasting the time of many to save the time of a few.
It also undermines their trust in you: if you're willing to force them to spend a bunch of time re-writing something that already works just to suit your whims, what's to say you won't do it again next year when you have a newer and even shinier whim?
Now someone will jump in to argue about how "FOSS developers are volunteers, they do it for free, you can't expect them to do the boring stuff". Which is false, false, and false: You'll find that for a large number of these projects (like say gnome and wayland) the core developers are indeed professionals who are paid (by e.g redhat) to work on it, even if they started off as volunteers. And the boring stuff is part of the job, too, otherwise don't call yourself a software engineer.
If you're working on a widely-used piece of software, then the users should be your god.
> They don't understand that even if Wayland had feature-parity with X11
See, I don't think you're giving them enough credit. Or is it too much credit? These are not stupid people. I say they
do understand this, they just don't care about your time enough to do anything about it.