I agree with you about the CSS preprocessors. I tried one once and was not impressed.
I think the difference is that I don't get paid. I have my own business. My revenue is direct from my end users. That is an anomaly these days. More importantly, it is a completely different mindset. I don't need to impress anyone with my resume. I don't need to impress clueless managers with buzzwords that they recognize, but don't understand. I don't have a development budget where I can pick and choose tools based on their cost rather than their value. What drives modern technology is almost entirely social. People want to impress with their buzzwords and the size of their budgets. The ideal, sweet spot is a set of frameworks that helps developers advance their careers with Shiny New Things and helps managers maintain a bloated budget to pay for it all. If you are one of the Big Boys, its all just free money after all.
It sounds like we have very similar mindsets. I personally make it a point to not use jquery because I want to be able to code whatever it does just as quickly with modern vanilla JS. But I'm also very intentionally pursuing being really, really good at JS. But that is very specific to what I do and suites my career as a "UI" developer well at the moment. Sounds like you are much more well rounded in your skill set than I am so makes sense to not invest extra time in learning bare bones es6 as a focus.
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