Python is popular because it's whitespace based syntax make noobs think it's easy to read. This and it's pre-installation on Linux made it popular amongst academics who embraced it for data analysis. This lead to a lot of data scientists embracing it and writing libraries for it which created a virtuous cycle in that arena.
And it's a damn shame because Python, and it's whitespace nonsense and lack of type system, is a horribly impractical language for building anything at scale.