Personally, my default was to pick up and is now if recognized contact pickup, if not and I'm expecting an unknown call, scrutinize, then if pickup, only answer with a cough or two — never "hello" or "yes" due to threat of voice cloning escalate to banks.
Spam is universally detested
My assessment is that voice calls are on the verge of going obsolete if the telcos fail to get a handle on spam. Yet the telcos behave as if they have no clue whatsoever and DGAF.
Consider: if you get harassed with a call or text you don't like, you send an SMS with that phone number to some known short code. You then receive $1 from the caller. If the caller cannot be found, the last verifiable link in the chain is responsible for paying the fine.
This would cause carriers to behave overnight, instead of allowing foreign call centers to spoof other people's real private numbers with your area code.
Where you are expecting a call and it's definitely not spam, but they're not going to be ringing from a pre-approved whitelist. Don't think they'd want to be putting $1 per call on the line and hoping for people to remember to click the right button afterwards
plus a lot of spam comes out of compromised phones, or compromised systems. what good is this if i have your phone, or just your SIM?