The cost of electricity (coupled with the rewards and cost of hardware) changes how profitable mining is. The more profitable the more players. The more players the more transaction throughput. This is exactly why miners have bought powerplants and why they operate in locations with cheap electricity, because it makes it more profitable for them. Bitcoin mining is directly related to the cost of electricity.
That said, not every cryptocurrency is reliant upon brute forcing hashing algorithms to verify.
Right people say that, but here in the real world we usually define some sense of sufficiency. Just adding more "security" by burning up all the worlds coal at some point has no meaningful benefit. This is just a nice narrative. Security is good -> more security is better no matter the externalities is a terrible way of looking at the current situation.
We don't make seatbelts out of titanium 8 inches thick with their own airbags when they're mounted in a go-kart.
When the hash rate dropped what, 75%, off the back of the China exodus literally nothing happened.
tl;dr: Same transaction throughput, same security, just less efficient.
That said, not every cryptocurrency is reliant upon brute forcing hashing algorithms to verify.