It is an interesting way of looking at the maximal potential of AIs. It could be that Oracle Machines are possible in this universe, but an AI built by humans cannot self-improve to that point because of the bound you are describing.

I feel that the phrasing "we have reached the upper bound on complexity" and later "can rise many orders of magnitude" gives a potentially misleading intuition about how limiting this bound is. Do you agree that this bound does not prevent us from building "paperclipping" AIs?