The nightmare case for whitelisting is an emergency call from or on behalf of your spouse or child using a stranger's phone. This is why I don't want a whitelist.

What I want is for spammers specifically to be identifiable and blockable, or for their business to be made prohibitively expensive. I didn't get spam calls on my cell phone 15 years ago, and as you say, what has changed is largely economics. Why can't we work to adjust the economics back?