I mean to say, what if we don't shrink transistors and keep adding them whatever thier size is and make a larger core? Shrinking transistors is causing alot of heat problem and CPU's are more sensitive to voltages.
The biggest problem with this idea is a term that I might be mispelling called the "reticle limit". It's essentially the limit of how big a chip you can make using the optical lensing system on a given stepper generation. On the current 90nm process technology, it's approximiately 30mmx30mm. I can usually find Google links to back up my assertions, but I'm not finding anything that mentions reticle size limits on Google... which leads me to wonder if I'm mispelling it (retical?).
In any case, whether Google is going to back me up on this or not, there is a limit to the size that you can make a chip before "edge effects" from the lens system cause errors. It has been gradually increasing from one process generation to the next.
That said, there are plenty of reasons why there aren't a lot of 30mmx30mm chips being made - in fact there are only a handful of chips being made at sizes even close to this limit. Those reasons have all been mentioned, but foremost among these is yield.