It would be so cool if Google could engineer that process the other way around. Instead of me giving Google my number, why can I not dial into a phone number of

It would be so cool if Google could engineer that process the other way around. Instead of me giving Google my number, why can I not dial into a phone number of Google (with my own number hidden). I think that would a) get more friction you need against the spammers and b) retain my privacy (at the cost of a phone call).