I am not really personally bothered by Python 3 being incompatible (with that one Jython exception that I already mentioned). But I would like to point out the comment https://news.ycombinator.com/item?id=13146127, I think you're the one who is wrong here.
> It's more likely that Python will suffer from people moving to other languages
Unlikely. Rails are probably going out of fashion. Javascript is a terrible language, which only saving grace is a decent support in browsers. I am not sure for what other reason, choosing a language today, I would choose Javascript over Python 3.
So people moving from Python 2 are most likely to end up with Python 3, I don't really see compelling alternative for them (unless they are going to something more functional like Clojure or Haskell or Scala, but that's entirely different discussion; for example I like Python a lot but I feel pure functional is where the future is, I find the imperative programming quite annoying these days, I would prefer Haskell, but frankly, I am not nearly as productive in it as I am in Python, because Python's focus on usability is very hard to match by any language).
On the other hand, I think Python 3 will actually gain in science and data analysis thanks to things like @ operator for matrix multiplication.