I really don't think the EAP testers or beta testers, as you referred to them a are getting early access to many of these incremental releases. If I had to guess, I'd say only the major releases get pushed out to those in the program. They'll probably get 8.1 before the rest of us, but the versions being pushed between now and then, I would guess, get some relatively quick internal testing, and then get pushed out to us.
In Tesla's defense, by and large the "bugs" we have been finding in these releases have been annoying, but, with rare exception, have not been safety issues. I'm not in any way attempting to make excuses for Tesla. But while the equalizer resetting is annoying, the car suddenly speeding up to 85 MPH unexpectedly, or veering into highway barriers would be infinitely worse.