The majority of automobile chips use transistor technology too large and primitive for a smart device of today. Current technology uses transistor sizes of 16 nanometers versus the automotive chip world of up to 90 nanometers. Sales of all the latest designed smart devices went through the roof when Covid hit and chipmakers reallocated capacity from the older, larger chips to the newer smaller chips to meet the shift in demand. Then there was a key supplier facility fire, and power outages in other plants that ruined things - a perfect storm for the lack of auto chip supply. Automakers really need to get with the program and redesign their systems to take advantage of the modern smaller transistor size that fabrication labs have re-tooled for and join the smart device chip modernization. From a business perspective, asking to build additional chip manufacturing capacity for today's ancient automotive chips is almost like asking Netflix to open a DVD movie rental store.
Auto manufacturers don't design their own chips for the most part, they purchase them from design and manufacturers in Asia.
Next, certainly not a zero-cost task, porting them to new proccesses is not a major issue, either, happens every day, and they are being ported.
The main issue is still capacity limits and covid and other supply chain issues.
It takes ~5 years and $ billions to bring up new fabs, much more expensive in the US than Asia.
The US is ramping up capacity, though, but it won't help for 4 or 5 years, and a large % is going to go for govenment purposes where they don't want designs handled outside the US for security purposes.
They also are cautious to not exceed requirements too much, or those $billions get flushed.