One thing that definitely happens is the maps are correct in SF and areas where Elon drives. They may also be able to make sure the planner handles some of those common routes well - not just for Elon but for the AP team and the internal testers (i.e. not employee, but full time AP team internal testers). All this can happen without them even realizing it ....
As I have said before - if roundabouts and school zones are handled properly - a large % of my drives will be intervention free too.
I think people who use FSD Beta rarely have more interventions because they are more likely to intervene at the slightest hint of the car not driving like the way they do themselves. As people use FSD Beta more - they have less interventions as they get used to how FSD Beta drives. There is a learning curve here.
This is self-reinforcing. People who don't get over this learning curve, will continue to have lot of intervensions and will not use FSD Beta much as a result. So, they never get used to FSD Beta and will continue to believe it to be very bad. On the flip side, those who use it often learn how FSD Beta drives and intervene less as a result. And they start feeling FSD Beta drives fairly well - with "known issues". I think this is where I am. So, you almost see those two "camps" here - those who use FSD Beta all the time and those who rarely use it.
But, every time I go on a drive I've used FSD Beta before, I tend to have more interventions, as I'm unsure what its going to do. After a few drives on that route the interventions are lesser as I know how it handles those routes.