That's scary - I have a < 1 yr old Tesla model Y and it is embarrassing how underpowered the tablet that controls basically every part of the car is.

Tesla's have pretty responsive displays.

The last vehicle I bought, I turned down several vehicles because many of the internal environmental controls were through a touchscreen, and the touchscreen was so slow and bad I was honestly astonished that they were selling it.

The salesman tried to downplay it but I still walked out of the ford dealership 100% because of their shitty controls/touchscreen.

Ended up buying a car with old fashioned buttons and knobs, much happier.

FWIW, Tesla is one of the few companies that actually put decent processors in their cars: in lieu of a cruddy, off-the-shelf ARM CPU, they use Intel (and more recently, Ryzen) x86-based machines. Their performance relative to the Cortex processors running in competitors is enormous, it must be slow due to the volume of processes Tesla is actually running onboard.

Isn't one of the big problems with Tesla vehicles that they use COTS hardware?

I'm sure I saw something about how they used commercial-grade touch screen instead of automotive grade, so they feel far nicer / more responsive than other cars but fail much faster as they aren't designed to handle repeated heating/cooling cycles that cars experience.

I don't need my car to drive itself with technology that doesn't work and requires me, pedestrians, cyclists, and other drivers as test subjects. I don't need my car to be powerful enough to compute simulations of the Earth's atmosphere. I just want a basic fucking car with good enough safety features. This fetishization of shoving chips into every square centimeter is ridiculous. I want to use my computer and drive my car, not drive my computer with all of the attendant software issues that'll inevitably crop up.

How can they not afford a 300 dollar tablet in a 40k dollar car?

A $300 tablet drops support in 90days to a year. A $300 tablet equivalent in a car has a trailing maintenance requirement for service and parts for years (5-10?)

A 300 dollar tablet dies quickly in the automotive environment with outdoors-like variation in temperature and humidity. Tablet manufacturers literally write in their product sheets "do not leave the device in a car or it may get damaged"; if you leave an iPad in direct sun for a month and it dies, it's expensive for you, if the same happens to a car console, that's expensive for the manufacturer which has to repair it under warranty.

The temperature range for iPad listed by Apple is 0 to +35 C for operation and -20 to +45 C for storage. The required temperature range for electronics on automotive dashboards (which may be exposed to direct sun) is -40 to 90 C, which effectively requires different materials, which means you can't even reuse most components.

assuming you're selling 5 million of a part where the previous generation is 5-10 years old, $1.5 billion is not a lot of money for development, validation, materials, manufacturing, logistics, dealer training, integration with future models, and a decade of OTA updates

Because it becomes a $3000 tablet, in today's chip-shortage environment, to meet certification for automotive use.

Oh damn. Thanks.