Your missing the point. Spammers call you from a spoofed number so that you think its someone near you based on the area code. I lived just a town over an invisible line in 2009, and ordered a new phone, and got an area code that the only other person I know that has a number in that area code is my wife. (920)

the ONLY calls that call me from that area code are spammers. if I get calls from any other area code, only 20% or so are spammers. Others are sales/marketing for IT companies, etc, and calls from one of the 2 area codes that cover my area where I actually live are usually all local businesses, etc. If I had to guess, I would say 85-90% of the 'spam callers' call and spoof the 920 area code when they dial me. that drastically cuts down on my automated messages about a car warranty that is about to expire.