Something worth noting is that FATCA essentially makes it impossible for an institution to remain "FATCA compliant" if they have any financial relationship with a non-compliant entity. Sure, they can have such relationships, but the U.S. Treasury department can then impose a 30% penalty on any transaction that passes through a U.S. bank. Given that the vast majority of international payments are made in USD, that 30% penalty is going to be very painful for any bank that purposefully decides to be non-compliant.

The end result of that will be that the global financial system is going to be bifurcated into "compliant" and "non-compliant" institutions. Believe me, most banks/insurance companies/financial entities will find it worth their while to eventually become compliant.

The reason that more countries aren't complaining about this (and most are actually entering into bilateral enforcement agreements with the U.S. Treasury department) is that they'll then be able to get access to the same sorts of information on their own citizens that the U.S. is getting on their own as a result of FATCA.