While I grant that you COULD be right, it doesn't seem to be the direction they're heading, quite the opposite in fact.
I use Windows hosted Ubuntu on a daily basis.
that's not the opposite direction. That's to familiarize their userbase with linux. Prepping everyone for when that becomes the underlying OS.
The unix subsystem for windows is a stepping point.
And Microsoft is all about progressing away from the local OS market and focusing instead on the applications, cloud based whenever possible.... and the services the os uses. They stand to gain much by not having all of that overhead in trying to make a secure, high performance OS.
I think it's a gradual conversion they're on the road to. Not adopting an existing distro...or just becoming a distro.. but something like what android is in relation to linux.