Exactly, I have moved companies from random web framework + random database to static site generators + CDN with high rate of success too. No point of using Rails/Django like stuff unless you have an extremely good case to, which is certainly not the Guardian use case.
Genuine question - because I'm currently doing CPR on an old Rails app with Mongo - what do you see as a "good use case" for Rails/Django and similar frameworks?
We used to use them internally for building a system management application that required talking to databases and an API that nodes could pull information from. This pre-dates system management tools like Chef, Ansible and it was just a tool like that. There is also workflow management tools that (like managing Hadoop jobs for example) that could be written in these. Generally, things where you need to deal with a lots of state (and state changes) from the outside world. I am pretty sure there are other use cases.