You need government approval (FDA or FAA respectively) to bring a product to market. Are you sure you want that kind of bureaucratic overhead (and the associated politics) in your car and home alarm?
I'm not sure if the FDA or FAA are capable of doing that, given how the government is really, really bad at building or contracting software (in general).
If only we could have some kind of standardized software to power these devices that is built by the community at large and thoroughly reviewed for correctness. Even at the cost of limiting hardware, I think that's an option.
Somewhat (but also not at all) like a more advanced ODBII[0]