A lot of people are not in situations where they can be cavalier about basically not being reachable by phone from someone not in their contacts. To be sure, the idea that we're always reachable is quite a modern phenomenon. Nonetheless, it's something of an expectation in many circumstances and behavior patterns take it into account.

The good news I guess is that, while I'm sure people vary, spam phone calls and texts seem to have gone down quite a bit for me to the point where they're a very occasional annoyance.