Isn't "emailing you first" just kicking the can down the road? What stops spam emails getting through to you? (Besides the exact kind of heuristic filtering you seem to be objecting to, that is.)

Email spam filters have the advantage of being able to see the content of the message, so hopefully they're more accurate.

The disadvantage of email is that it doesn't work for urgent use cases, like Disneyland calling the parent of a lost child.

Disneyland will have a handful of IPs and phone numbers, and I'd bet my hat will have a team aggressively calling any ISP or provider that flags them as spam.

Even better : ignore unknown numbers, real unknown people can leave voicemail.

(Hopefully leaving voicemail keeps out of reach of spammers, I guess it's just too expensive for them ?)