Interesting comments, gang. No, 1080p is not obsolete by any means. Nor did I intend to suggest that this is the case. As Aaron pointed out, "normal" HT screens (up to, say, 120-130" diagonal) would probably not benefit from anything much above 1080p resolution. It's sort of the 720p/1080p argument all over again on a larger scale (pun intended.) You'd have to get REAL close to notice a difference and this wouldn't represent real world viewing situations.
Let's not start putting all those wonderful 1080p projectors up on eBay just yet.
Perhaps the higher resolution 4K and above technologies will be more appropriate in direct view situations providing "photo quality" with movement unheard of (or unseen) before. Who knows? It's much too early in the game to see where this is all going.
But I've seen the future of higher resolution projection brought off the drawing board and at least on the threshold of possible high end home applications. (4K has been around in limited release theaters for a while now.) And we all know that today's "high end" becomes "middle of the road" more quickly than anyone imagines.
That's the nature of the technology.
Exciting and scary at the same time.