The community is entrechend in 1.5 because that's what everyone is now familiar with, IMO
That probably has some weight to the community's decision to still use 1.5. Other reasons (and more important IMO) why we're still stuck on 1.5 is due to nerfing 2.0, and the plethora of user trained models based on 1.5.
I'm continued to be amazed by the quality possible with 1.5. While there are pros and cons of each of the different offerings provided by other image generators, I haven't seen anything available to the public that can compete with the quality gens a competent SD prompter can produce yet.
SDXL seems to have taken off better than 2.0, but nothing so amazing to justify leaving all the 1.5 models behind.
But note that SDXL is really awful in automatic1111 or vanilla HF diffusers for me. You have to use something with proper augmentations (like ComfyUI or Fooocus(which runs on ComfyUI)).
Yeah, comfy was given a reference design of the sdxl model beforehand so it would be supported when sdxl was released. I should probably switch to comfy, but I don't touch the tech very frequently as I don't have a practical use case besides the coolness factor.
FWIW, "everyone had gotten so used to 1.5 that they just didn't want to bother with 2.x" might provide a similar mechanism, if a very different place for the blame: if people aren't paying attention to the new stuff you are building, it is going to hurt your "support".