>Things like jQuery, underscore, etc...
Sounds great until you have a team of 5 developers maintaining at least a semi-huge code base over the course of some years. Some people leave, new join the team.
Then you really start appreciating frameworks if only for their conventions to structure the code. Top coders can write web apps with jQuery and underscore alone, but everyone else is better off following some conventions.
If your code degrade over time, sorry to tell you, a framework won't solve the problem.
If you have coders that don't care about maintainability of code correction, code organization in whatever technology, they won't care about what you wish.
As usual, they won't take the time to learn the frameworks, will diverge, and you are back to square one with no code that can be salvaged or reused. (at least with vanilla techs you may salvage stuffs)
I think you use frameworks to solve the wrong problems here: you are probably the problem by trying to ditch the lack of real engineering skills in IT (not the letter of engineering. The spirit: making things that are correctly built and are reliable over time... like a plane).
This is all nice and well in academics and start-ups but some years down the road, your code is going to be a mess. Frameworks, especially opinionated frameworks are a tremendous help. Coding in jQuery or native JS without some prodding is at best an accident waiting to happen.