There's some misunderstandings here. For one thing, there are obviously skilled people working at every salary level. What you're missing is that this is largely irrelevant. Relative compensation (in software) is a shockingly good proxy for all the associated support and people investments to support them. Employees that cost less are less supported and thus less enabled to produce high quality work than their better-paid counterparts, as a very rough rule of thumb.
It's my experience that OEMs are significantly less invested in their developers and the quality of the software they produce than any FAANG. They don't consider software to be a core competence and they rarely invest in the technical expertise to understand quality or push it internally.
The scale of dev costs is also pretty minor for vehicles as a whole. Amortized labor costs are typically on the order of 10-20% per vehicle. Devs are a small portion (~100s-1000s) of the tens of thousands of engineers that work at major OEMs and their suppliers. An extreme 2-3x wage increase would end up as a few percent increase, but the truth is there are cheaper ways to do that than salary. "All" they have to do is care about the software components the way many do about the mechanical components. It's a cultural problem rather than a strictly monetary one.