Capitalism combined with a functioning legal system. If your competitor isn't advertising according to the rules (e.g. Tesla, because there are seemingly no rules in the US?), then competing becomes difficult.

For example Mercedes has some autonomous driving features, but due to fake US marketing from Tesla, even I have some voice in the back of my mind that perhaps the Tesla version works better, while the specifications don't agree, IIRC. That is, Mercedes offers higher guarantees in the EU than any Tesla model.