Nah. I'm a long-time Python developer (10 years+) and I moved everything over to Python 3 because there are so many advantages. This includes a number of massive internal code bases that I maintain at my day job. Porting is surprisingly easy nowadays, it used to hurt a lot more.
Management is fine with development time spent on migrating to Python 3, since it's an investment in the future (Python 2 will be EOL in 2020!).