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.
