That isn't what they said. They carefully explained that they could migrate to Python3 but that the benefit of doing so was small so they looked at the performa

That isn't what they said. They carefully explained that they could migrate to Python3 but that the benefit of doing so was small so they looked at the performance benefits of using other languages and decided that the performance benefit was large. The performance benefits of using Go (or Kotlin) were the deciding factor. My guess is that the framework for them thinking about this is that they have already been thinking about migrating languages to get better performance and the Python3 migration seems like completely wasted effort if you then throw it all away to go to another language shortly after.