You've probably heard of him but Kitboga deals with scammers from India all the time. I just pulled his most popular video. But he has probably hundreds:
Indeed, intelligence doesn't play a key role in avoiding scams. It appears that some of the most intelligent may be more prone to being scammed as well.
Good info on detecting and avoiding fraud and scams:
https://www.jw.org/en/library/magazines/g20040722/How-to-Protect-Yourself-From-Fraud/
This doesn't have to do with phone scamming, but with a job I used to have a long time ago. At that time I worked for Echostar the parent company of Dish Network the satellite service provider. I dealt with dealers all day. Helping them if they had questions about commissions on installations or selling equipment, etc. I noticed one strange dealer who was activating every single apartment in a large apartment complex in Miami, Florida. There was something very fishy about the way this dealer was operating.
I don't know how it operates today, but when I worked there we would give around $300 to a dealer for a new subscriber. A $100US for installation, and two other payments one called Flex, and an activation bonus. Not bad money if you can get it. Turns out this family from a southern country had come to the United States, had been scamming Echostar, reporting fake installations on this apartment complex to the tune of stealing over $100,000 in payments. By the time I caught it and reported it, they were long gone. Who knows to where.
There were other scams you would see them do. For example they might call in and activate all the satellite channels on a receiver. The receiver would have a smartcard, and we would send a ping over the satellite to activate the channels by opening access on the smart-card. What they would do is after activating the channels, remove the smart-card, call in deactivate the channels and wait about a month, that is when the ping would stop going through it usually ran in a cycle. Then they would hook up the receiver, stick in the smart-card, and have full access to all the channels for free. Imagine them charging a customer a fee to provide "free" satellite. There were a lot more scams but those were a couple. I am sure it's changed a lot since then that was over 20 years ago.