Actually, it's Windows NT 5.1. 2000 was 5.0. It does stand to reason that being a .1 release, there would be nothing but some minor changes, while the big ones were left for a major version.
As to why 95 and not NT? MS made claims that DirectX above version 3 couldn't work on it. Guess what... it could, they just intentionally broke all their installers so that it wouldn't.
You have to remember the mindset of MS... there's "home" and "business". You can't just make software that's good for everybody, no... that's what is done with Linux, or Mac OS X... instead, you make different "noob" and "paid noob" versions. This way, some dipshit in a suit and tie will want to pay you $800 for the same junk that you sold to him for $200 on his "home" computer.
The amount of lipservice that MS pays to "corporate" and "business" users is near the level of farce. The new MSN Messenger on OS X has separate "Personal" and "Corporate" tabs for different lists. There's no way to make the Corporate tab leave. It's there, whether you use it or not.
And this... this is where their big problem lies. They sell "business software". You can write shitty software and they'll buy it... you don't need quality, all you need is a snazzy logo and a lot of "corporate" branding, and they'll be on it like old folks at a buffet. Just shit out some code that barely runs, and these cockmasters will pay thousands of dollars for it. They'll be more willing to pay if you offer things like "subscriptions", "Genuine Microsoft Partner" shit, and "expensive tech support".
Funny part is, these same tactics that sell software to businesses, gets it into the hands of users, because who installs the software? Business. HP or Hell or whoever uses the same "busness" mindset to buy Winblows. Moron users think that it's because it's "good", when in reality, it's just the opposite.
Fuck 'em all.