I see your point, but I think when migrating over a million loc, it's a question of practicality. Incrementally migrating a project from Python 2 to 3, between which at least large-scale architectural patterns are more-or-less identical, is a completely different story from migrating to Golang, which uses drastically different paradigms to structure code and think about data flow.

Reminds me of some of the points made here: https://www.joelonsoftware.com/2000/04/06/things-you-should-....