Dude, this is just dumb.
I will put it as simply as I can.
Realism is not always the intended outcome.
There are uses for AO, Reflection pass, refraction, and so on ON TOP of the final render, because more often than not you want to emphasize a detail or a mood that will require those passes, as the intended result is not achievable in real life.
For the SSGI I’m very interested in adding AO to it, and I even used RTAO with it, but RTAO has some limitations + performance cost. The point is, I can tell you for a fact that SSGI is not sufficient to define the contrast between surfaces, the difference between it and a baked scene is night and day.