They are VOIP calls. And many are outside the US. And it's not just the robocalls- but I can't tell you how many calls I get a week about extending the maintenance plan on my car.
And frankly, someone is buying this shit. Else they wouldn't call. I mean if 1 sale is made for every 5,000 calls they've made their money. Same with scammers. Who the hell is going to fall for a robocall from the IRS? A call that's barely in English, and comes from a local number? Obviously, somebody does.
There was also a push in the 90s to make a kind of "postage stamp" where the cost of sending an email was CPU, which would have had the same effect of prohibiting spam by making email too expensive to spam with. ISTR the guy who came up with that idea (or one of the guys) has had an interesting series of projects since. Can't remember much beyond that, though.
Too bad that didn't work out for snail mail. The post office got addicted to the income, gives them super sweet deals, so users are maximally annoyed while the post office grabs maximum profit.
It's just ridiculous that every shared mailbox (like an apartment) has a giant recycle bin next to it full of mailers.
I feel like more of that blame lies with the government as a whole than the post office in particular. They have to get innovative when they don't take Federal dollars, get dollars taken from them, have to fund retirement of their employees out further than other agencies, and can't close offices. It surprises me that it stays afloat despite active hindrance from the government at large.
And frankly, someone is buying this shit. Else they wouldn't call. I mean if 1 sale is made for every 5,000 calls they've made their money. Same with scammers. Who the hell is going to fall for a robocall from the IRS? A call that's barely in English, and comes from a local number? Obviously, somebody does.