Quoting a recent Hacker News comment of mine (https://news.ycombinator.com/threads?id=tromp)
In other words, the lack of people mining at a loss makes mining profitable and hence subject to forces of centralization.
There are several reasons why mining as a lottery substitute is rare, a major one being that commodity hardware is inefficient by many orders of magnitude, making even a botnet next to useless.
Perhaps, if a proof of work, whose efficiency gap (with custom hardware) is at most an order of magnitude, were adopted (or slowly phased in), enough lottery players would arise to make mining unprofitable at scale.
Botnets should then just be welcomed as a modest increase in decentralization.
However I don't expect Spondoolies-Tech to support this vision of unprofitable mining...
Disclaimer: I designed Cuckoo Cycle