I tend to describe my issues with Rails in a nutshell: it felt like everything was optimized for day 0 instead of day 30 or 300.
Devise was the ultimate example of this. `rails generate devise:install`. Instant authentication system with almost zero changes to your code base.
Yet now something as central and important as authentication is implemented outside of your application in some highly abstracted software. To do something as simple as figure out the name of the cookie it sets, you have to either dive into its internals or look at the actual cookie it sets instead of just reading code that should've existed in your code base.
Rails was the first "language" I learned so I was its best case subject. It was able to indoctrinate me in the beauty of metaprogramming and things like that. Yet that still wasn't enough to keep the light from shining through the veneer when working on a real world projects where you just want to know how something works by reading application or glue code, not daisy chaining through a bunch of library code or hoping you cache-hit the library's FAQ so you don't have to deep dive.
There seems to be a lot of "why is there no Rails in {JS,Go,Rust,Clojure,...}" lately and it's no surprise to me why there isn't. The same reason Ember and Meteor never took off to the degree that React did.
There was some sort of "glue code just isn't that bad" renaissance.