There are alternatives such as cutting the internet cable or requiring insurance on all cross jurisdictional transactions.

Those are not alternatives. VPNs and botnets already exist. We have minimal practical ability to control Internet traffic or transactions between most foreign countries. All it takes is a single compromised device in the USA for the scam traffic to get through.

There are very few transatlantic cables that carry all of the internet. It would be very easy to cut them. VPNs don't make any difference.

Come on, be serious. No one is going to cut any transatlantic cables just to prevent scams. VPNs make a huge difference: as long as you can get a route out somewhere then you can use a VPN (possibly to a compromised host) to make your traffic appear to be coming from another source.

You can't VPN on a non existent path. Or bomb them. All it takes is an actual desire to stop scammers.

We are heading for a period of a not-fully-connected internet. Already people are cutting off China and Russia from their sites because their bot traffic is either overwhelming or malignant.

Afghanistan just cut all the fibers.