Universal parts is one solution. If 80% of the parts work in 80% of the cars, you solved a huge portion of the problem.
And once being tied to a vendor there's no real incentive for right to repair etc.
let's stop repeating this nonsense. You wouldn't say LVMH has minority market saturation in the clothing industry, because it doesn't compete in the global clothing industry. It competes in the global luxury goods market, where it has a dominant market majority control. Similarly, Apple has, and for a long time has had, a near monopoly on the luxury electronics market.