There's no way to know the timeframe but tipping points can come very suddenly. I've seen a number of companies get stuck with a large code base built on old t

There's no way to know the timeframe but tipping points can come very suddenly. I've seen a number of companies get stuck with a large code base built on old technology and it causes them huge problems, chiefly around finding people who can (and are willing to) program with an obsolete language. Companies with large Python 2 code bases will make things easier for themselves if they start making the transition sooner rather than later.