I live in $civilized_country and have gotten one unsolicited phone call ever. It was from an Indian, so either it was a scam or someone who doesn't adhere to telemarketing blocklists.
Do not blame USA's inadequacies on human nature.
If it were not for human nature, no intervention to prevent scammers and telemarketers would be necessary.
People in the US don't get uniform amounts of spam calls, so I'm doubtful that your experience can be taken as representative of your entire country.