IMVHO, ASIC hardware provides such a huge efficiency boost that even if everybody in this planet ran a mining raspberry pi, the ASIC manufacturers would maybe still own more than 51% of the hashrate.
At 2 MH/s per pi, times 7 billion people, you get a paltry 14 petahashes/s. That's a hair over 0.2% of the network...
You'd need three trillion raspberry pis to get half the network. Good luck with that!
[1] https://en.bitcoin.it/wiki/Non-specialized_hardware_comparis...
[2] http://lifehacker.com/how-the-raspberry-pi-3-benchmarks-agai...
IMVHO, ASIC hardware provides such a huge efficiency boost that even if everybody in this planet ran a mining raspberry pi, the ASIC manufacturers would maybe still own more than 51% of the hashrate.