Secure boot doesn't require disk encryption of any sort, that's simply a common additional feature that the RPi happens to support. Being able to change the public keys without a verified key update inherently violates the ARM security model here.
Normal users care about secure boot because it protects their disk encryption.
The point of secure boot is to make sure it's only our firmware running, and only our firmware connecting to our backend with the appropriate keys. Anything else is a security nuisance at best and an company killing problem at worst.
We're willing to sacrifice the SoC in those cases. Your mileage may vary.
Second, you're creating e-waste when you go out of business. This is not something that should be legal.