Situation isn't post scarcity if there is fierce competition among the various AIs for resources... and if they are expansionist..
Just finished it, a nice story. Although I don't think the Ultrabrights expansion was realistic. They were changing whole star systems into computronium, but their capabilities didn't seem to be an order of magnitude greater than the predatory Superbrights in actual practice.
"Can't stand to spend any time in realtime." etc. Well, they could/should just edit themselves to be able to stand it.
Just as the Superbrights should have just edited themselves to not need mortal lives for sensory input.
Just my opinion, but even at sub-light expansion fronts, such runaway growth, given the age of the universe and even just Population II star systems/planets, if even one intelligence has gone this way, we'd see evidence of it, or not be here because Sol and planets were already colonized/consumed.
I see two possibilities.
1. Grey goo or strong-AI galaxy-eating computronium scenarios don't really happen.
2. They do happen, and we're living inside a simulation.