jQuery isn't actually "fading" per se, it's still used in many (MANY) projects, if only because it enables you to use pre-made plugins without reinventing the wheel. But like any library it has its flaws and the growing number of full-stack pure JS users have been vocal about the fact that they could do without it. Which is true and fine, but it's equally ok to rely on it for what it is: a time-saver.
Typing this, I realise I recently vocalized my hatred for Bootstrap and other frameworks for reasons that are comparable to the ones people use to critique jQuery. After all, both save time even though there are other ways to do it. The thing is, Bootstrap isn't just a library of functions built on JS. It's that, plugins built on it and a lot of CSS that you'll often have to overrule. So why should you use jQuery without too much consideration (some is still relevant, as other posters have said) but really ponder using Bootstraps? Well because jQuery's weight is a fraction of Bootstrap's and it mostly won't hinder the rest of your coding while saving you time. Bootstrap without care is jQuery plus lots of added baggage, a fraction of which you usually use, and a lot of wasted time battling its base styles.
In short, if you're using jQuery because you need a couple plugin and are faster ad coding with it, go for it, no harm done. If you're not actually using intricate plugins and just simple functions you could do in pure JS, consider the second option. And for front-end frameworks, steal their ideas and organisation (reusability of code is king) but don't rely on them in the long run. They were made for prototyping and lazily building back office when the dev can't be bothered to do CSS. Use them for that.