Just imagine a $130 2100k @ 4.5GHz+
Intel is scared to make this, because right now they have people willing to spend on the 2500k, but an unlocked dual would be adequate for many while saving a few bucks.
Most games that "make use" of quads only have 1-2 cores heavily loaded, with the other 2 cores at light to medium loading. Pretty much the ideal usage scenario for a 2C / 4T HT product. I doubt you'll see too many games that have 4 heavily loaded threads, because aside from enthusiasts, few people have quads... they'd cut out a large portion of their potential customer base. The exception, of course, being games like GTA IV... poor code quality console ports from companies that don't really care about PC user experience, as they're primary customer base is consoles.
Aside from gamers who needs more than 2C / 4T? People doing heavy video editing or compiling?