True, but that's been the case for 10 or 15 years now. Most of the applications we develop are just CRUD applications... with a twist.
There seems to always be some detail that prevents you from having a generic backend. I mean look at something like SAP. It's an off the self application, it pretty much contains everything you'd imagine needing for running a large business. Yet every single installation is customized like you wouldn't believe.
Most of the stuff you mention isn't making the backend go away, it just makes it a little easier to implement and run. Just throwing EVERYTHING into a Hadoop cluster seems... careless. You'd still need to validate that whatever the client sent is actually any good. Otherwise you're potentially polluting your data. I don't believe in client side validation as something that provides any kind of usefulness, beyond giving helpful hints to the user.