This is probably a stupid question, but if heat dissipation is a big problem, why can't we just build better cooling systems: bigger heatsinks, refrigeration, etc.? I'm not an electrical engineer, so I'm sure there's something I'm missing.
At this point it's getting heat out of the CPU to the heatsink that's the problem. How close the various transistors are makes getting heat around them and out of the CPU.
For given system cost, any marginal dollar spent on cooling requires a dollar less on silicon. Also, cooling isn't scalable so there are seriously diminishing returns above ~130W.
