Instead of trying to eliminate scam calls from coming in try the following....note, since natural voice/sound carries a different frequency than that of a recording, is it not possible to identify or distinguish between the two via the use of current information technology in conjunction with applied advanced telecommunication solutions.
Because the two sound(s) differ, what if you were able to engineer voice identification software that can interpret or determine real voice calls verses recorded calls. This particular idea/solution may already be viable via (Voice Recognition) or similar technology.
How can this possibly work? Similar to caller (ID) which affords one know who's calling, (VFI) or voice frequency identification lets you or the receiving device/phone know if the incoming call is original voice or recorded voice, maybe.
If a software application can be engineered for receiving devices/phones then such devices could actually screen and/or maybe terminate these particular voice recorded calls. The one problem that I see is how will this program/function identify what could be a legitimate voice recording. Not sure but maybe now is the time to have alternate numbers for family, friends, clients and colleagues but not necessarily have more than one communication device unless one opted.
Together with caller ID this approach could/should substantially decrease the number of calls one physically answers, maybe.
I think it's safe to say that you/we have very little to no control over how often your/our phone rings. Beside that's what it is designed to do. Yet no matter how often it does ring you have total control over how many times you choose to answer it.
Substantially decreasing the amount of these particular calls should be the first approach and if that proves successful then you maybe able to successfully manage and/or contain the activity at a projected lower volume.
If the solution requires a drastic change in our national communication system, we'll adjust like we always do and because most of these particular calls are foreign based it can easily and justifiably be sighted as a National Security concern.
Probably not much of a solution sited in this summary, technology is not my forte. Maybe this will stimulate those in the IT, Telecommunications and Electrical Engineering field.