Companies would rather refund your money than ever “Open Source” fucking anything.
Why? Because then they can’t charge you for the new “CarThing” two years later, when they try again with a different product.
Letting people have access “under the hood” would mean new products would be competing with the “open” CarThing.
It’s just like companies throwing out perfectly good food and getting security guards to guard the dumpster, because if people got food for free, gosh oh golly, it might bring down prices and impact profits and companies can’t have that no-no.
They will burn it all to the ground to make a profit.