I agree with some of the quality criticism and all of the stress full-stack dev causes. But: in the early days, front-end applications lacked many concepts of software architecture. It was defined by a pronounced "whatever works" mentality with no separation of concerns and scripts, layout and presentation mixed wildly together. Then came frameworks like backbone and GWT which introduced rigid architecture design concepts into the web-dev discipline, which wouldn't have been possible without heavy inspiration (and experience) from back-end design.