My suspicion is the less profitable mining is, the more decentralized it will become.
Bitcoin grew too rapidly in value for it to stay decentralized, but mining farms don't make a lot of sense when the payout is small.
Sure, anything can happen.
Chinese electrical rates could go up around x10, so folks in Belgium can start mining.
It might become substantially cheaper to buy a single miner, instead of a warehouse full of them.
Bitcoin could get banned in China; factory mines become impractical due to Vesuvius-like IR signature (shoot a heatseeker, randomly, up into Chinese sky, odds of it locking onto a Bitcoin mine: 100%).
And, of course, Mom'll never have the heart to mention electrical bill to her 30-yr-old Bitcoin enthusiast