Maybe I'm not aware or not done my homework. But I wonder if there's a service that allows our phone number to be wrapped by another number. That way we can give our original number to only trusted parties/family and the wrapper number to outside world. In which case if we receive too many spam calls, we can simply change the wrapper number.
That sounds like Google Voice, that’s how it works for me:
You have one physical real number and one number that is attached to google voice. You give the google voice one to random parties and the physical one to your friends/family. All calls to google voice will still reach your real phone, but they will be routed through google voice first. You can later discard that number and get a different google voice number.
GV will also ring >1 phone if you choose. So, for example, an inbound call to your GV number could ring both your cell and landline phones and you pick up the one that's more convenient for you.
