You are basing that on todays technology. It is like a guy from the 90's saying you will never get iphone os to run on a mobile phone.
Eventually the tablets will sport some seriously crazy hardware which will still be overkill for anything anyone is going to use it for. You will never need a hexacore 3ghz processor to send an email.
Exactly! Really, the whole reason netbooks exist is most people (me included 90% of the time) dont use anywhere near all of the power in the CPU of their PC. So you can have a low spec CPU in a nice case and still do most of your computing from it.