Django is very much like Rails with the same upsides and downsides - it's easy to get started, but hard to maintain and upgrade, partly because of not having a type system. So companies making things for long-term internal use tend to prefer these Java frameworks, because while it's horribly cumbersome to get started with them, you can be pretty confident that upgrades will be safe because they put a lot of effort into backward compatibility.
Strongly agree about the difficulty of maintaining a Django project due to its lack of type system -- though tbf, it's imposed by Python, the underlying language.
And, one can annotate Python3 to make it typed, so things might improve.
