Well, the universe is very heterogeneous, you see. There's still plenty of hot, dense, and fun to go around, you just have to look in the right places!

“Red galaxies? On a Friday night? They’re so hot and dense and full of obnoxious Level III civilizations, nobody goes there anymore.”

Colder is actually better and more fun. You see, the theoretical lower limit for how much energy your super-computer takes to run is given by temperature, and thus on a larger scale by the temperature of the background radiation in your part of the cosmos. See https://en.wikipedia.org/wiki/Landauer%27s_principle

occam's razor says probably not

Says who? Have you considered the alternatives?

Maybe that's another Great filter in Drake's equation - civilizations dumb enough to go full scale in crypto mining and 'AI' to generate cute cat pictures with nobody to stop for a second and think a bit. Those last few tokens will take half of universe's energy to mine, lets hope we are on the other side.

This is what happens once you start down the road of making Paperclips…

Too soon.

"It looks like you're telling a transhumanist parable. Would you like help?"

https://www.decisionproblem.com/paperclips/index2.html#-game