Most "legitimate" robocalls from a school or doctor's office are better off as SMS. Does an appointment reminder really need my immediate undivided attention? If it's not worth having an employee manually make the call it's probably not worth my time to answer.

Sure, maybe they should be that way. But until they are that way, this doesn't seem like a feasible solution.

Legit automated services tend to be opt-in and allow me to specify sms, eg our provincial health service notifying us about vaccine availability.