Not to mention the Total War series, though they are significantly different in some respects. I think the problem with traditional RTSes is that they are just too damn hard to play effectively for most people. As a former follower of StarCraft II, I remember vividly the discussions about ladder anxiety and even experienced it myself when playing. It's such an incredibly high-pressure game, I'm really not surprised people avoid playing it.
There are plenty of browser based RTS games in they don't have turns. However, total war is much closer to starcraft etc than any of these: http://www.mmobomb.com/browsergames/strategy
Just because the RTS genre is small doesn't mean that it makes sense to consider things that are very different part of the genre -- having construction/replenishment, strategic movement, etc., outside of the realtime game and part of the turn-based game makes Total War very different structurally from an RTS, and very different in its appeal.
Who gets to decide which structural features are allowed and which aren't allowed in the genre? I'm sorry but I've had this sort of argument with tons of other people regarding other genres. Personally, I don't think you can define strict rules for what should/shouldn't be in a game for it to be classified into a genre. Otherwise a genre would be nothing more than a list of games that never changes.
Not really. Starcraft 2 comes to mind. And not too long ago Supreme Commander. Wargame: European Escalation... and so on.