As the hash rate drops by 50%
If this happens all of a sudden, I'd wonder if someone is trying to do a 51% attack with the remaining hash rate.
The game theory still stand, so IMO it's unlikely to happen unless they don't care about wasting lots of money.
some kind of security system to prepare BTC to fight against any eventuality.
IMO it's not realistic to prepare for
any kind of eventuality.
Another nice solution would be to better distribute the miners geographically but I'm sure that will happen over time, maybe even placing some in orbit.
I doubt it'll happen over time unless each location have affordable electricity cost and there's effort to prevent Bitcoin mining banned by government.