At one point I worked on the very systems they used (dialers, PBX, internal CRMs), with the carriers that enabled it. This wasn't an opinion of mine, I was merely passing along real-world information from someone who worked in the industry (me). Many in this thread completely underestimate the volume these centers call at. We aren't talking hundreds of thousands of minutes per month per center. We're talking millions of minutes. Cost per minute is a massive cost even at 1/6 increments. The call center we ran, that was direct marketing / support typically had telecom bills well into the 6 figures every month at the height.

Their scams are purposefully asinine. It's not profitable to spend time and effort into tricking the wise into an unwise act. It's far more profitable searching for the unwise to act in kind. So when you throw your hands up asking "Who would fall for that!?" The answer is typically: Someone who'd be willing to buy a gift card or share bank account info. This contradicts your last point that a given locale is more or less likely to be scammed given the native language.

Language barriers are a part of the issue, yes, but these centers are capable of calling and speaking a number of languages. Cost and regulation are the big factors here. Just like any other business model. I got out of the business (telecom / direct marketing saas) right when EU started raising fees and coming down on some of the bad actors. Unfortunately for the US, that meant those bad actors focused even more in the US.

Also, the scams really aren't as profitable as you'd think most of the time. They generally can't afford more than a $50 CPA at best. Again, they have to turn heavy volume to get to their target market. They also rotate "offers". You hear about the big "wins" a lot (Grandma scammed for 50k+) but those are outliers. Typically it's $20 here, $100 there. Again, volume.