I would be happier with something the manufacturer was confident was serviceable. Control boards that approach the cost of a high end smartphone are unreasonable, but also common.
I wonder, truly, if this would be successful. I have no way of even wrapping my head around how to get something like that off the ground.
I think if someone designed and shipped a car, for instance, that was completely serviceable by the owner and designed with that in mind first and for most, you could easily disrupt the car market for a very broad amount of people today.
In the last 15 years, I can only recall one time a car went into a shop for a reason other than the above and that was an independent shop where I was too busy to deal with the job. That's across a Mercedes, a Jeep, a Honda CR-V, and Alfa Romeo, and some classic Mustangs.
There are a few marques that are DIY-unfriendly (hello, BMW), but most cars can be effectively DIY maintained. A DIY-friendly car would not be as disruptive as perhaps you think.
Combine that with trying to keep parts compatible over years and you would develop a following.
I don't want a good warranty, I want a well working equipment.