I'm sorry, what? Last vestige? That's not even close to being correct. Off the top of my head, here are some websites that still have a separate mobile domain:

I'm sorry, what? Last vestige? That's not even close to being correct. Off the top of my head, here are some websites that still have a separate mobile domain: YouTube, Facebook, Reddit, Twitter, and a whole host of smaller websites as well. Granted, many of these do some kind of automatic redirect, so that you're redirected to the appropriate domain for the device you're using regardless of the link you follow. But none of them do the kind of responsive-design-and-media-query approach that you're talking about to differentiate between desktop and mobile.