See herehere footnote 38, which discusses the OU policy about countries that at least have the regulation, even though they don't have government inspection. (Basically the OU will allow it if they find the company to be in fear of the government). This ends up including China, Poland, Lithuania, and Ukraine.
However, I have heard from someone in the Kashrus industry that more recently the major Kashrus organizations agreed to stop allowing milk from India and China without it being Cholov Yisroel, based on a specific, extensive investigation.
Some have called Mexico a failed state, however the local certification does certify non-cholov yisroel. I don't know how accepting those outside Mexico are of that.
I do think that ultimately those who are more lenient are relying on the economic incentives more than the government supervision (as really Rav Moshe Feinstein does himself at some point in his Teshuvas, pointing out the huge cost of covering it up vs. the gain of using non-cow milk). There is simply no real industrial logic in using non-cow milk in industrial production in most of the world today.