In my opinion, the consoles release just fine the way they are. But I think they are trying to focus more on media capabilities than a video game's gameplay.
Nintendo is an exception because they always work on the games and less on fancy stuff like the graphics. PS3 and Xbox 360, I believe do focus on anything else besides the video games they make. Nintendo actually takes their time to make their whole franchise successful.
Anyway, that was getting a little off topic. But your point is well taken. A whole year is a long time, so by the time the next console hits, the last one would have already died. So, I think the consoles move out at a steady rate. I don't see how they rush into it.
Of course, this is just me talking. Ignore me, if you want...