there are exactly zero traditional linux clients with any kind of market penetration. And most of the growth you can account to steamOS. There's no reason to make new users suffer through a 1990s model.
also if I come back as combative that's not my intended tone. I'm just like, how much failure does it take for people to realize that no one wants a traditional linux desktop any more.
Some of it is intertia. I will wholly admit that I took a while to even TRY an immutable because I have decades of traditional Linux desktop history and "it works just fine! Why change it!" - then again, I was still compiling monolithic kernels for quite a while after the Linux kernel first got module capability, so maybe I just get stuck in my ways