The first of which is that Laos, Cambodia, and Myanmar all together only have a GDP of about $100 billion. 90% of these scams are run from that region of the world. The second is that these sorts of analyses end up unknowingly including the addresses of so-called "P2P exchangers" i.e. unlicensed but not necessarily entirely black market currency exchanges such as hawaladars. If one of the fraudsters converts their Tether to another currency with one of these exchangers, that address will be labelled as "fraud" even if all of the exchangers other customers are legitimate (informal money transfer systems are used for remittances in a lot of the world). The fact that unofficial exchangers often have business relationships with each other also even further complicates analyses that look solely at on-chain data. Lastly, no existing analysis, including by companies like Chainalysis, even comes close to $75 billion.