I'm with Ackmed -
Each step towards realism requires a much bigger leap in processing power, as we approach the target, the curve becomes much steeper. People have been pointing to rendered CGI as examples of what we'll see in the future for ages, and frankly, it isn't happening.
IMO, games now are just not that much better than they were in 2003. But compare 2003 to 2001 and you see a real difference. I'm sure people will jump in with examples of X game that is just so great compared to what came before, but I'm not buying it. Compare any x-year period since the development of the 3D card, and you will see improvements are tapering.