Though, when it comes to prototyping, I think Rails is a much more convenient option. In Rails I can launch a working CRUD app with authentication in 10 minutes, literally. In Django I have to manually create directory structure, manually specify each route mapping, create and program controllers (views), etc. Django doesn't even have a built-in authentication templates, only controllers (views), so I end up writing this boilerplate over and over again. The other thing is that the authentication requires a username and password, which feels kind of clumsy, when every other authentication relies on email and it is not very trivial to modify that (built-in admin dashboard relies on built-in authentication for example).
Someone still had to create that database with those tables in it. It didn't magically pop out of the aether. Your complaint, then, is not "you must define every bit", but with where you do it, since you have to define things no matter what.
And if you have an existing database you'd like to use with Django, 'manage.py inspectdb' will reverse-engineer a set of model definitions from it.
If you have an existing database, sure, Rails is preferred. If you're starting from scratch, the Django definitions can create the tables for you. If you do have existing tables though, you can use inspectDB to have Django create the models for you.
This is where people fear the “magic” of things like pluralization of models to table name and introspection... but it’s all just code! You can read it and look at it and understand it. No magic here. Just convenience and a smaller mental model as an end developer.
Also... resources as a first clsss citizen is the biggest reason and the reason it defeats Django for this use case. You define ‘resources’ in your routing layer instead of just routes that map to a function. This allows you represent multiple crud actions with a single controller and even nest them, all with a few lines of code. Then you get access control for free on your sub resource, knowing you’ve already passed the parent checks and have that context.
Example: /users/:id/photos/:id
In this case, my Photos controller will already know who the user is (and if they can view these photos) based on work that the parent did. It’s single responsibility principle. You can even have a top level photos resource devoid of the user context and support both cases with minimal effort.
Yes, you can do these things in Django. But it’s not designed to make these things composable and seamless. I’d argue it’s not REST-friendly. Don’t even get me started on Django Rest Framework which is a massive beast in and of itself.
You get all of that out if the box on Rails. You can stand up extremely robust and ergonomic API’s with so little code you’ll feel like your cheating.
I should probably write a blog post.