Intel also still has a lot of Brand power behind it, so there’s that. Regardless of other possible reasons, for some people that’s enough, for a variety of it’s own sub-set of reasons.
Other than that, we honestly don’t really know how it performs compared to other options, as we don’t have real benchmarks yet. We could find the extra cost is more justified than it looks like, or we could find it’s just a premium for extra power without going into the much higher end.
For that matter, we don’t know if the new AMD 2920X Threadripper at $650 will be proportionally worth the money over the i9-9900k either (or whether it will perform better at all in most applications).
EDIT: Forgot you asked about some linux bias as well.
Last I saw, the 2700X is a bit faster on most benchmarks in Linux compared to Windows 10, a bit slower on a few though. Threadripper 2990X is at times significantly faster in Linux than on Windows 10. I don’t know if Intel chips show a similar effect, but that could make some of Intels edge, if it’s real, diminish when looking at linux (but, again, I don’t know the intel comparisons in linux).