> Is there some reason telcos couldn’t block them before? Yes, the FCC normally requires carriers to put all calls through. So the FCC is only now, very belate

> Is there some reason telcos couldn’t block them before? Yes, the FCC normally requires carriers to put all calls through. So the FCC is only now, very belatedly and in very limited circumstances, allowing deviations from the FCC's own rules that have prevented carriers from stopping robocalls for all these years.