In my opinion, Rails is only really great if you have a very tight correspondence between your routes, your models, their JSON, and the database tables. When you start separating those apart, that's when you start to suffer a lot with rails.
In a number of cases, I've found that the Rails Way was smarter than my original assumptions.
If you’re mostly writing CRUD apps, you’re correct. But the world is not all CRUD, even if you’re only looking at the web space.
If you need a screwdriver, then stop complaining about how much your hammer sucks and get a screwdriver instead. Or ask yourself if a nail could work in the same situation.
I don’t think it’s a problem, nor do I think it’s specific to rails. All technologies work best for the cases they were designed for, that’s how design works. Rails was designed for CRUD apps, and it’s brilliant at that. The trick is knowning when you’re not making a CRUD app.
Rails assumes some very basic, predictable, and consistent naming conventions by default. Beyond that, it has virtually no assumptions about what data feeds into a particular route or controller.
For instance, if I have a controller named 'dashboard#index', at /dashboard, that controller doesn't care if I have a Dashboard model, or UserDashboard, or if I have a 'dashboards' table in my db, or a collection of 50 other random models that all combine to create a dashboard on the fly. If I have a 'people#update' route, it makes no assumptions that I have a Person or People model or db table. I can put whatever I want into that controller action with zero penalty.
Generally speaking I am going to align my controller, model, and route names, but that's more for readability and maintainability concerns, not for the benefit of the framework.
This is a very simple example of a common task that the separation between UI and backend fails.
Rails has never made the promise of giving you every a solution for every situation in the wild right out of the box, and I don't understand why people seem to think it does. No framework could ever do that. What it does is abstract away the common stuff that makes up probably 95% of most web apps, and gives you the ability to roll the rest on your own.