Any totally new solution is liable to be useful only to an increasing minority of the population over at least the next few decades.
It would probably be easier to graft authentication onto the current system and force individuals to post a tiny bond per assigned phone number.
Let people report robo calls and cause robo call originators to forfeit their numbers and bonds and don't allow them to buy new numbers under the same identity or credit card.
Even paying $10 per per 10 robo calls placed would boost the cost to $1 per call.
If you need 1000 bullshit calls to scam $500 out of someone then your net is negative.
If you want a solution, whitelisting isn't it. You could even create them at the organizational level, like schools and government offices publishing lists of numbers to be whitelisted... But that would just be used by the robocallers, spoofers and scammers.
We as a society benefit hugely from instant communication and trying to remove it today would put too many people at risk.
If the government calls you, you're really in trouble. Calls from the "government" are almost always a scam. Same with banks to a lesser extent.
The school issue is an interesting one. Schools ought to have other methods to contact parents(or students). At the very least, a school should be willing to provide a list of numbers to whitelist.
My point is that there are difficulties in not taking phone calls, but there aren't as many of those difficulties as one might assume, and they exist in large part because nobody is pushing for obsolescence of the phone in favor of something better.
I wouldn't even mind a system that wasn't IP based so long as it had better security measures. In fact, that'd be preferable to relying on proprietary systems owned by the likes of Facebook and Google. The fact that a Caller ID can be easily spoofed, that numbers themselves can be spoofed, and that phone companies have long been complicit in the criminal activity that goes on over their system, is absurd. It can't be fixed and should either be thrown away or rebuilt from the ground up.