Sort of, but I'd rephrase it. I don't need to understand how a harddrive or SSD actually works, I just need a consistent and well documented abstraction.
But Rails (and Ruby) do offer that. I agree that there's a lot of it, but it is there. Its abstractions are consistent, and Rails is generally well documented.
I don't know Rails enough to really comment on that, but if it takes 1 years to learn it all, I'd say it fails my definition of concise and comprehensible. It should fit in a single volume book that I can read in the evening over the course of a week.
That said, I don't have a problem with frameworks that are larger. Hell, I'm a .Net dev by day myself and that certainly doesn't meet that requirement. I just don't find it elegant.