I have heard a big factor is that a lot of the newer devs don’t really use desktop OS outside of work. So for them developing a desktop OS is more of an abstract project like for me developing software for medical devices which I never use myself.
People who got into software development not because they enjoy working with computers, but rather because it pays well. Outside of work, they're the same as any other casual who's got a phone as their primary computing device.
Also people who now have other commitments, such as family, or became tired of computers over their career and don't want to fiddle with them outside of work anymore. I feel like an outlier in my office, even the nerdiest of my developer colleagues sold his PC in favor of Steam Deck and phones.
> any other casual who's got a phone as their primary computing device.
I tried to use my phone as a "computing device", but i mostly can use it as a toy. Working with text and files on a phone is... how to say nicely ... interesting.