In the mainstream, which is apparently all anyone cares about, the West Coast did have a lengthy hiatus.
Personally, I couldn't give a **** less about who is doing well in the mainstream since I rarely listen to the stuff anyways. For my tastes, the West Coast never left thanks to Quik, Suga Free, Dilated Peoples, Murs, Madlib, etc.
I could also say the same about the East Coast during the years that Southern rap has taken over the radio waves. There is a gang of good music coming outta NYC, but it just isn't **** the average consumer will come across without looking for it. THAT is the real problem, IMO.
I think people get too caught up in this coastal ****. The truth is that the mainstream **** from both sides generally is lacking in replay value and quality, so essentially people are claiming that we have the best garbage artists that people actually know about. Want proof? I can almost guarantee that the rappers that respond to Kendrick who are actual spitters will probably get overlooked by the masses (think Joell's rebuttal) in favor of the "hot" artists. People just want a show and some bars they can use for a new meme. Most don't really care about actual skills because if they did, they wouldn't say dumb **** like "NYC has been garbage".