Yup - in particular VAT tax evasion (i.e. a company putting a $2000 sticker on laptops when they pass through Bermuda) is something that the US could easily solve with a minimal cumulative VAT tax - it just chooses not to.

The same corruption that leaves tax loopholes all over the place will prevent sanctions against tax havens - them existing is a desirable state by the corrupt that can purchase influence to perpetuate their existence.