Do you guys think 4K projectors will be affordable in about 2 years?
Is that too long for someone to wait?
No, I don't think so.
At this time there are nearly NO 4K projectors on the market. The major manufacturers aren't in the game and even at the pro level they are very difficult to come by. This means that we are likely a couple of years out of seeing 4K products come in at the prosumer level - which may be $30,000 or more, which means 5 years, or more, until you see $5,000 units.
If at all.
That last line is due to the big question mark as to whether or not 4K displays are even going to make sense at the consumer level since no sources above 1080p are currently available. For perfect pixel-for-pixel resolution 1080p is the magic resolution which is likely to be the new 30 year NTSC type standard. Considering that there is zero indication that Blu-ray will have any physical successor, it likely means that HD downloads will be the future, and they aren't even touching the quality of Blu-ray Disc at this time.
So, we are looking at perhaps ten years before we even have a viable format which can consistently deliver higher than 1080p resolution to consumers.
At that time, displays beyond 1080p may become the norm, but that's a long way beyond what you asked about.
On the professional side, they are doing 4K encodes of films and 4K distribution, but this is tens of thousands of dollars beyond the average consumer's wallet.