[dgb23]

Not to mention that engineering expertise is just the potential. You then also need the time and the willingness to actually do that kind of tedious and potentially slow moving work instead of all the other things on your list. And as we all know, the list of things that can be improved in any system typically grows over time.

The 'out of the box' or naive and un-optimized performance of something is the baseline. And with something as huge and self-contained as a database you want the happy path to be fine in terms of performance.