Linux desktop environments are developed by its users wanting the best experience possible.

Windows is designed by a committee that tries to do as little as possible and has ulterior motives higher on the priority scale than UX. Like marketing copilot and other Microsoft subscription services. Microsoft software is always aimed to be just good enough for the users to not choose something better. They love just coasting on their marketshare without doing much to improve. Like they did with internet explorer and now do with office.

> Linux will only have a good desktop environment when it's users will be willing to leave it.

Putting aside the debate as to the quality of desktop environments, I honestly hope you're being intentionally nonsensical as a joke. What you describe can only make sense under the grossly misinformed belief that "Linux" is a monolithic entity incentivised to stop its users from "leaving it", and that this mythical "Linux" would have the agency to decide it needed "a good desktop environment" in order to avoid that from happening.

I recently started using COSMIC and I would definitely call it good, even if it has a few rough edges due to just recently coming out of beta.

Linux has had several good desktop environments for well over 20 years.

When is Windows going to get a good desktop environment?

I mean, from my perspective Linux has multiple good desktop environments. I've used both Cinnamon and KDE for years and have found both perfectly pleasant to use.