My beef with tesla, is that is is their black box to access, and not yours. I think you should own your data. That is to say nothing of their toxic assult on right to repair.

Your beef is with the entire auto industry then. No one gives you access to the flash memory in the airbag module storing these last values prior to an incident.

AIUI, the police can pull a fair amount of data from the onboard OBD port on cars. I'm sure the manufacturers can get even more out of it.

Yes you can get a lot of data from ODB. I use a bluetooth OBD reader and Torque Pro to get data, view fault codes, reset them, etc. I haven't used it to get historical data but I think it's doable as you mentioned.

They already have a 'black box' which contains their logs. This is how they have been able to investigate the previous reported crashes.