You just aren't worth their time, so they except you to stick to public documentation, buy their dev kit, and figure out out on your own. Want to use a part without public documentation? Tough luck!
Many companies are a lot more friendly to small customers, though.
Also automotive customers tend to stick with their long term partners. It's why Renesas, Infineon and NXP(former Freescale) own the automotive MCU market.
Chips are usually sold in reels of 1k or 3k. For quantities like 10k chip vendors will just redirect you to a distributor like Mouser or Digikey - who will be able to ship an order of 150k to you next-business-day without any issues.
The problems start when the chips you want aren't redistributed. You're a rounding error to the manufacturer. Why spend the time and effort assisting a startup with a one-off 10k order when the next email is from a large car manufacturer placing a guaranteed 15M order?
Same with NXP. Salaries and bonuses are very good(by European standards, ignore FAANG wages) but the overtime, work pressure and workplace toxicity makes that a difficult proposition if you can't stomach the ascension to the level where the REAL money starts to come in.
There are indeed people at these big semi companies who can slack off and collect huge paychecks but those are the exception, as some people in the trenches are burning the candle on both ends to make the deadlines of masks reaching the fabs on time.
The churn level is high. People are constantly fired, let go, or leave after their relocation bonus expires if they don't see any promotions after their tolls.
Tooling is also very specific. There are gazillions of scripts written in all possible languages for all sorts of semiconductors. Some colleagues will happily backstab you not sharing information about their tools.
Oh yeah, that sounds familiar.
Unfortunately the location is undesirable at the moment.
For reference https://www.linkedin.com/posts/george-hotz-b3866476_comma-3x...
https://www.linkedin.com/posts/george-hotz-b3866476_qualcomm...
Slightly ironic given how geohot has been ranting on stream non-stop for the last few days about how terrible it is to work with them for his comma.ai self-driving startup