Living in the Bay Area, California: Our landline gets between 3 and 7 robocalls/day. My cell, maybe 3-4 a week. It's infuriating.
fwiw, my elderly father uses a cellphone. The only time we can't reach him is when he leaves it inside to go outside, and then a landline wouldn't help him, either :P
I often get back to back calls with one bearing my landline prefix and followed by one to my mobile with its prefix (both numbers undoubtedly spoofed).
Although once I did get a phone call from Adobe, back when they had that big userinfo leak. I thanked them for the call, but said I wasn't going to do anything over the phone, they could contact me through my email address, which they did. So that's one legit one, at least.
I have to leave our house fax unplugged most of the time for the same reason. It is a genuine annoyance.
https://complaints.donotcall.gov/complaint/complaintcheck.as...
Then click Continue and view the list named: "What was the call about?".
This tactic may work for landlines, where prefixes are similar in particular neighborhoods (at least in the US). But for cell phones, it's actually a dead giveaway for many people. This is because prefixes are less correlated to location. For example, I have only ever known one person who had the same prefix as my cell phone. So whenever I see a matching prefix on the caller ID, I know it's a spoofed robocall.
But it's possible that these robocallers actually don't mind that people like me get wise to them in this way, because they'd rather only reach less tech-savvy targets, who don't know about caller ID spoofing.
This is like how spammers are rumored to use well-known tropes in their messages because then the only people dumb enough to respond are "qualified leads" that are more likely to fall for scams.