Big parts of miners nowadays probably don't even have a CPU or any computing ressources beyond a RaspberryPi...
not sure about that, maybe Ghash-wise new rigs produce more, but as a quantity of peers, GPU rigs still beat everything, it will never go away in parts of the world where electricity is available cheap, it'll always bring fair profit for many in fiat terms... Even in case of RaspberryPi it could work, that device is 5 times faster than http servers 15 years ago and with a much better broadband...
using just the random distribution for open source cloud sourcing could solve some of the even bigger issues... perhaps exchange sites don't even have to be hosted from start, but rather just the quotes and charts from all, sites to stay independent and the distributed infrastructure within the new layer could serve as a ticker available to everyone, nearest available miner could be your first http mirror for charts... dispersed, low transport of data... now we have centralized exchanges web sites with heavy volume of data transport mostly on ticker requests from bots and impulses of system outage, completely opposite of what produces efficiency...