I can tell you from experience of trying to work with a dance company in Cuba, when I informed my bank, they froze my account, leaving me high and dry in Cuba. When I managed to get back home to UK on money lent from family in UK, and grill my UK bank for the reasons why, they informed that they need to respect the wishes of "International Customers".

My account stayed locked for 18 months, of course bankrupting my company, as it was.

That is the reason no one tries to do business in Cuba.

To be honest, I think US sanctions will be the downfall of the US, and everyone else in the Western world. They will reap the seeds they sow.