
Isn’t it the other way round?
Difficulty drops because miners are losing money while mining and shut down miners, which by protocol makes the Bitcoin network adjust to the resulting difficulty (happens each 2.016 blocks afair).
Let more and more miners shut down and you get an idling amount of mining power capable of attacking the network. Why would they do that you may wonder. Well, shorting BTC, attacking the network and cashing in could be a way to recoup their losses. Mining equipment isn’t cheap and letting it idle makes no money.
I’m not saying this will happen soon or at all. I’m just saying it can happen. It’s one of the flaws of proof of work (PoW).








Last time I checked it was automatic and done each 2.016 blocks, which should ideally take 14 days time (10 minutes per block at average).
When the difficulty gets adjusted, it gets automatically set to a level, which would take exactly 14 days to mine the next 2.016 blocks.
https://en.bitcoin.it/wiki/Difficulty
I’m no friend of PoW in general and even less so of the way Bitcoin implemented it (resource hungry arms race for specialized hardware compared to PoW done only by general computing devices cough Monero), but insinuating there’d be some manual adjustment is disingenuous.