They laid off SDETs circa 2014 (I was one). I don’t think Windows ever had QA people, but it did have automated testing and dedicated people to write and monitor those tests, then file bugs if something broke. But not anymore since 2014.
These days, the only testing any release of Windows gets is from Microsoft employees (Dev/PM) and Windows Insiders.
They have rules of how many hours of self-hosting are required before they can release, but that’s the only requirement. That there exists telemetry of it running.
You might see a gap with that testing methodology, but it might also explain how things like this happen. If it’s a bug that doesn’t prevent boot, it’s easy to ignore.
(I knew a few devs who would just put builds of windows on one of their computers and play a 72 hour long video of a black screen on repeat to get self hosting hours. Then they would proceed with their feature release. And nobody saw any problem with that.)
MS needs a 'windows xp sp2' moment. Where they stop jamming new things in and just fix as much junk as possible. They still have a mixed control panel situation. Things just randomly work/break for no real reason. Camera here one day gone the next oh look its back again. Hey my sound is broken again. Linux/MacOS in many benchmarks is faster. Hundreds of old programs now just flake out for random reasons. But then will work again sometimes. Backwards compat is a reason to stick with them. But if it doesnt work, why am I here? SteamOS is going to remove one of the large reasons people keep windows.
MS is losing the people who cared about using them. Those people are migrating to linux/macos. I dont blame em.