I think you are intentionally misrepresenting this and moving the goalposts to make your point. GP blamed safety and liability for the way the process looks like, not the complexity of the task. When it comes to safety you bet that an improperly installed or inspected wheel or tire can be dangerous.
A short internet search tells me [1][2] that some sort of tire malfunction causes tens of thousands of accidents and kills hundreds of people every year in the US alone. That doesn't include wheel malfunctions (e.g. wheel coming off). Yet this isn't locked behind some manufacturer approval and proprietary tools.
How BMW chose to approach this is profit driven. The old money printing machine from ICE maintenance, repairs, and spare parts is slowing down so they come up with new ways of extracting money. Like making the lives harder and more expensive for any non-BMW shop to do repairs. They're not alone in this, other brands do the same.
> If you would see how EV Clinic "repairs" Tesla batteries, you would not say they have any concern for liability.
More moving of goalposts mixed with not understanding what liability is, and where it belongs. So you tell me what's Tesla's liability when EV Clinic "repairs" a battery.
[1] https://www.smithlawcenter.com/practice-areas/defective-tire...
[2] https://www.safetyresearch.net/nhtsa-gets-real-on-tire-fatal...