It's possible that the kernel and core components are still robust, having been developed in a time when engineering standards were higher. As far as I know, the kernel is still basically Dave Cutler's NT kernel, adapted by his team to 64-bit in the early 2000s, and his stuff was always well reputed for stability, though other teams were producing unstable code.

The problems of Windows today always seem to trace back to the early 2010s when Satya Nadella took over and nuked the QA and testing team. That's borne out by what we learn from the current article series, which describes how those test engineers who weren't fired were parachuted into roles they often weren't prepared for. And in Windows this seems to have led to a culture of hasty, undertested patches, shoved out to users and re-patched when users report problems, but not before. Also, again borne out by this article, a managerial culture of pressuring devs to add new features (that users don't even care about) instead of solidifying what's already there. You end up with demoralized devs and a teetering tower of technical debt.

If the core of the OS is robust but everything on top of it is flaky, then the user experience is still going to be of an unreliable OS.