Unpopular opinion:

When people make the argument against AML/KYC regs that "we spend $100 for every $1 of money laundering caught" they're basically saying:

"we spent $100 on this lock but no one broke in"

The whole point is that it's supposed to be preventative.

We should be placing the burden of proof on this system to show money laundering *prevented*. The true answer is probably close to zero.