>More likely we’re just going to max out around human levels of intelligence, and we may never find a higher level than that.

I've seen people state this before, but I don't think I've seen anyone make a scientific statement on why this could be the case. The human body has a rather tight power and cooling envelope itself. On top of that we'd have to ask how and why our neural algorithm somehow found the global maxima of intelligence when we can see that other animals can have higher local maxima of sensory processing.

Moreso machine intelligence has more exploration room to search the problem space of survival (aka Mickey7) that the death any attached sensoring/external network isn't the death of the AI itself. How does 'restore from backup' affect the evolution of intelligence?

Granted there are limits somewhere, and maybe those limits are just a few times what a human can do. Traversing the problem space in networks much larger than human sized capabilities might explode in time and memory complexity, or something weird like that.