The criminal money and money laundering has been researched since 19th century. It has stayed at constant 2-5% of world GDP. However the cost of compliance has gone up exponentially.

Today banks use $250B/year on KYC checks. You could fix the world hunger and still have $50B leftover money with this amount.

It's not a fair comparison. Money laundering controls likely have also been implemented since the 19th century in some way shape or form. Therefore, that 2-5% figure also includes the effect of those controls. This might just the natural equilibrium below which the juice is no longer worth the squeeze.

Access to information and interconnectedness have also increased exponentially so it might make sense that the costs have increased proportionately.

Finally 200B/year would not solve world hunger if nefarious actors grift away most of that money (especially because you wouldn't be able to track them with out some form of KYC)