The speaker considers 10^45 floating-point operations a possible soft upper bound, not a guarantee, for the compute needed to produce intelligence through a nature-like training run.

“on it for a billion years you know with that amount of compute and and and the thought there is that you don't really need to understand how intelligence works at all if you're building it with that type of training run because there's no insight coming from you it's you're just sort of letting nature do its thing and letting evolution take its course and so so the thought is that we can make those not guaranteed but like a soft upper bound at something like 10 to the 45 and then you can make other sort of soft upper bounds you can think”