What Is Better: One General Model or Many Specialized Models?

"We have 60 churn models in production." I asked them why so many. They replied that they own 5 brands operating in 12 countries and, since they wanted to develop one model for each combination of brand and country, that amounts to 60 models. "Did you try with just 1 model?" They argued that it wouldn't make sense because their brands are very different from each other, and so are the countries they operate in: "You cannot train one single model and expect it to work well both on an American customer of brand A and on a German customer of brand B".