I think the two big problems with the Python 3 rollout were a lack of compelling reasons to upgrade (at the time - many big features have been implemented in Python 2 in the years since), and upgrades like this being inherently scarier in dynamically types languages.

If Go 2 brings improved error handling and generics, those are HUGE reasons for the community to get onboard and upgrade quickly. Plus with compiled languages, the upgrade is way less scary - so many errors will be caught at compile time that can sneak through as subtle bugs in dynamically types languages (unless there’s GREAT test coverage). Also, Go 2 may not even bring breaking changes! Though I’d imagine some things will still break no matter what (code analysis tools, programs that use variable names that become keywords, etc.).

Maybe I’m being naive, but I think Go 2 will be adopted quickly with relatively little pain, as long as it brings super-desired features like genetics and error handling improvements.