At least they did not sell it (like UK)...and some countries did dump some $ in form of treasuries.
I should have qualified that I was mostly referring to the latter.

US very often has a "unique" policy, like taxing citizens for worldwide income (even though they don't live in US currently), not being a part of CRS, etc, etc.
US have some jurisdictions that are very enticing for foreigners to open accounts and trusts in, including famous South Dakota trusts.
https://www.theguardian.com/world/2019/nov/14/the-great-american-tax-haven-why-the-super-rich-love-south-dakota-trust-laws

Interestingly, there is no reciprocity: US citizens would have at least some difficulty opening up accounts abroad (or at least have stringent reporting rules on those) due to FATCA laws.
Switzerland lost 85% of American clients as a result.