IMO, 90% of so-called 'MVC' applications are actually MV applications.
In a typical Rails application (or one of the myriad frameworks inspired by rails), the code in 'controllers/' is actually view code that happens to be written in Ruby rather than in the template language of choice.
The controller is actually in config/routes.rb.
But as you mentioned, this is actually a good thing for most Rails apps. If your app doesn't need a controller, putting a controller in is just over-engineering.
MVC for the web was basically taking MVC for the (Mac) desktop, where it was invented and made sense, and slapping the name on something different because Rubyists love Macs.
In a typical Rails application (or one of the myriad frameworks inspired by rails), the code in 'controllers/' is actually view code that happens to be written in Ruby rather than in the template language of choice.
The controller is actually in config/routes.rb.
But as you mentioned, this is actually a good thing for most Rails apps. If your app doesn't need a controller, putting a controller in is just over-engineering.