But we do run biological computations (assuming that the exercise of human intelligence reduces to computation) to make em technology possible.

Since we're just bouncing short comments off each other at this point, I'm going to wrap up now with a summary of my current position as clarified through this discussion. The original comment posed a puzzle:

Brain emulations seem to represent an unusual possibility for an abrupt jump in technological capability, because we would basically be ‘stealing’ the technology rather than designing it from scratch. ...If this is an unusual situation however, it seems strange that the other most salient route to superintelligence - artificial intelligence designed by humans - is also often expected to involve a discontinuous jump in capability, but for entirely different reasons.

The commonality is that both routes attack a critical aspect of the manifestation of intelligence. One goes straight for an understanding of the abstract computation that implements domain-general intelligence; the other goes at the "interpreter", physics, that realizes that abstract computation.