"UI wise there is the same issue. Someone used to Windows 10 or 11 would find a transition to Windows 2000 more jarring than to say Linux Mint. ReactOS is no longer a «get the UI you know» proposition, it's now «get the UI of a system from twenty five years ago, if you even used it then»." "A perfectly working ReactOS would already be incompatible with what current Windows users expect."

That look and feel is the easy part. That can be addressed if it's really an issue. The hard part is the compatibility (that is given by many still missing parts) and stability (the still defective parts). The targeted kernel matters, of course, but that is not set in stone. In fact, there is Windows Vista+ functionality added and written about, here: https://reactos.org/blogs/investigating-wddm although doing it properly would mean rewriting the kernel, bumping it to NT version 6.0

I'm sure there will indeed be many users that will find various ReactOS aspects jarring for as long as there are still defects, lack of polish, or dysfunction on application and kernel (drivers) level. However, considering the vast pool of Windows desktop users, it's reasonable to expect ReactOS to cover the limited needs for enough users at some point, which should turn attention into testing, polish, and funding to address anything still lacking, which then should further feed the adoption and improvement loop.

"No, people will never be switching to ReactOS. For some of the same reasons they don't switch to Linux, but stronger."

To me, this makes sense maybe for corporate world. The reasons that made them stick with Windows has less to do with familiarity or with application compatibility (given the fact that a lot of corporate infrastructure is in web applications). Yes, there must be something else that governs corporate decisions, something to do with the way corporations function, and that will most likely prevent a switch to ReactOS just as it did to Linux based distributions. But, this is exactly why I intentionally specified "for individual use" when I said "switching to a stable and functional ReactOS, at least for individual use, becomes a no-brainer". For individual use, the reason that prevented people to switch to Linux is well known, and ReactOS's reason to be was aimed exactly at that.