Well, not completely unsolvable. But nobody would like the solution.
What all these scams rely on is a way to transfer money in an irrevocable fashion. Restrict that in meaningful ways and you end a lot of the abilities for these scams to operate.
You could, for example, outlaw gift cards as a start. You could force the likes of Western Union to have a holding period before releasing money. Crypto would be hard as any regulation against it is pretty easily circumvented, but you could outlaw crypto currency exchanges (I'd worry less about crypto though as it's pretty hard for grandma to reliably setup).
Difficulty in setting up a money transfer is not a hindrance. I have heard stories of scammers walking someone through the entire process to getting a mortgage on a house on the A&E Intervention episode of Greg. If they think you have money and they think you are gullible, they will devote time and effort to getting it.
High schools should teach how to spot a scam. As others have observed, this is not a new one, it's just gotten more high-tech and convincing. This is one of many practical things our schools should teach about that they just don't.
These scumbags send grandma to a Bitcoin ATM.