That's just if we're operating in a 1950s future paradigm, where you need to do everything with regular humans running around and occasionally colonizing neighboring solar systems when things get crowded.

If we're allowed to do a bit of virtualization, then things get more interesting. We could get things a bit more compact if we take a few centuries at the start of the project to develop solid brain emulation technology to ease those pesky problems of needing lots of living space, sleep, and eventually devolving into stone-age cannibalism with mystery cults around permuting ten word sentences. Estimating the computation involved in human cognition is tricky, but 1 exaflops is floating around. Say that a well-engineered and focused emulated mind can evaluate one permutation in an average 1e4 seconds, a bit less than three hours, since it doesn't have to worry that much about maintaining a society.

So that means the exhaustion process would require 1e18 * 1e4 * 1e40 = 1e62 computation steps. A kilogram of Drexlerian nanocomputers appears to be able to do something around 1e25 flops.

So if you were in a big hurry and wanted all simple new ideas ruined in just 300 years, you could just grab Jupiter, turn all of it into drextech computronium, and fill it with your loyal EM programs. A technologically advanced Kardashev II civilization might end up having exhausted a lot of simple ideaspace after a single millennia of hanging around in a single solar system.