- The best-governed language in all of software, and the best-governed web framework
- A huge ecosystem of libraries for everything from data science to email processing, that are (mostly) easy to read and modify and free from systemic security issues. And pretty much every major company with an API has an official Python library for that API.
- The standard language taught at most of the top CS programs around the world
- A web framework that's had almost no major security issues over the 10+ years its been around
What exactly would you get in terms of benefits from switching to Ruby? I'm not saying Ruby or Rails are bad tools, I just don't get why someone who already knew Python and Django would switch.
I get that if you run a dev shop it might be a better choice for just cranking out web apps as fast as possible for clients, but if you run an actual startup I don't see that the benefits of saving a couple lines of code would offset the costs of being locked into the ruby ecosystem.