Years back, when Caller Id was still fairly new, there were a lot of areas in the USA that did not have Caller ID, that is, if someone in these areas called you, your phone would not show their number. I knew people who wanted to block incoming calls where they could not read the callers number or identification, but were afraid that they might miss an important call from someone calling from one of these areas.
Is most of the country now on Caller ID? Other than callers who deliberately block their number when calling, should you expect just about every call coming in to be identified by Caller ID?
Caller ID across multiple networks depends on carriers cooperating with each other, never one of their strong suits. I’ve read that there are actually financial incentives for the carriers to do a half-assed job. It costs them extra money to do it right. While they are happy to charge their customers insanely high margins on caller-id, they hate to pay other carriers pennies for the database lookups needed to provide the service.