There are many thinking this way and many thinking the better way off... If everyone would ever to do this, then it will be possible for so many newbies to make some good coins generated using their CPUs only, as the difficulty would have dropped down hard due to this and blockchain may get stopped and no ledgers might take place...
Difficulty drops are limited and they happen very slowly, and blocks still need to be solved before the difficulty changes. It would take 10 years before the difficulty would drop back to CPU mining levels... Bitcoin mining already has contingency plans built into its design to make these ideas pointless.
In the
very unlikely chance that the hashrate were to fall to levels low enough to allow CPU mining a viable option again, the network would likely need to be forked to allow for an one time difficulty adjustment sooner then 2016 blocks.
The only thing that I can really see causing this to happen would be if we say a very long, sustained drop in the price of bitcoin (over probably 1+ years)
