Microsoft tried not to increase the minimum specs required over XP very much. This lead to certifying a bunch of underpowered hardware as "built for Vista" which lead to many, many people having super slow computers. On top of that, the UAC used to be a security boundary and it would prompt very often because Windows software had been written to behave like it was on a single-user system and mess with system files all the time, so it was really annoying.

I also had little trouble with Vista and liked it well enough. But I had plenty of RAM, I believe it performed badly with 1 GB or less. And of course people got hung up on UAC.

That’s kind of crazy. Firefox and libreoffice don’t do well in 1 Gig of ram but at least they’re doing something. You can run a decent DE and few decent apps in 1gig just fine with most Linux distros.

And Microsoft Word ran perfectly well on 16MB of RAM in Windows 95, back in the day; and even better on NT with 32 or 64MB, productive and more than comfy.

I guess my point is that running decent software on what today would be considered very little hardware is a solved problem, but it's not what the economy is optimized for.

The difference here is that LibreOffice is still maintained (in fact, the math typesetting in Microsoft office is practically unmaintained at this point and is just miserable to use.) Old windows (and old Linux) have serious problems that modern OSes don’t have. You can run modern good and compatible software in very little ram and the only reason not to is because someone else is forcing you or you’re just not aware.

Obviously you're not the only person, but the data points to a flawed release.

For me, Vista was slow as molasses, which was enough to upset me and make me hate it. For a lot of people, it also had driver problems.

No. It was Windows Longhorn. Microsoft abandoned it.