While I agree that there are a handful of use cases for catching all Exceptions, if you look at some of the 5 million hits you found in github, the vast majority are not such cases. They are mostly try/except blocks that wrap a particular operation (a dict access, a raw_input call, etc). You don't want to automatically translate "except Exception" to something that involves ExceptionGroups, because most of the time it is not needed -- the code in the body can't raise ExceptionGroups.
Your first email on this thread showed that you were able to quite quickly, just from what's already in the PEP, think of how to do what you need for your valid "except Exception" use case. My feeling is that people who need it will be able to do it quite easily. I'm more worried about people assuming that they need it when they don't.