The thing about Intel is that they expect relatively large profit margins on all the products they sell.
AMD is fine with smaller profit margins. Considering their position in the CPU market, they can't afford to be picky about margins. They need to price stuff competitively to get people using their products.
This is something I've thought about, though. And you have to keep in mind that the GPU in SB takes up a fair amount of die space as well. If you get rid of that (which Intel plans to do with the SB-E chips), that frees up room for another two CPU cores that you could add without even increasing die size compared to current chips. It seems like it would be extremely trivial for Intel to sell 32nm products with 8 cores or possibly even more, as long as clock speeds were lowered enough to keep TDP in check. Whether AMD will provide enough competition for Intel to bother releasing SB chips with more cores is another issue, though.