jQuery is used on 83% of all websites; React is used on 4% [1]. You’re right that people are probably using it differently than they were a decade ago, but even in 2021 your average jQuery question is probably useful to many more people than your average React one.
Today, so many things are possible and easier with plain JavaScript and/or CSS.
I'd even go further and say there's lots of new sites using jQuery unnecessarily because the accepted, highly-upvoted, but 10-year-old SO answer said that was the way.
No one should be recommending the introduction of jquery (to solve some discrete issue) unless it’s already part of the stack.
But that’s exactly the opposite of how the current state of JS answers appears.
[0] https://insights.stackoverflow.com/survey/2020#most-popular-...
Of course, that doesn't really matter — we're talking about Stack Overflow users, and you're right that this is a way better source of data on what Stack Overflow users care about. Not sure why I didn't think to check their developer survey.
There are a lot of websites I made in the past and they are still online and many of them use jQuery, but I don't need to check Stackoverflow in relation to those websites, because I'm no longer working on them (and in most cases no one else does either, they just happily keep running unmodified). All of those are part of that 83% that you mention.
Stackoverflow is a Q&A websites for developers so IMHO it should focus on tech that is currently in use on actively developed systems.
50/10 vs 4*(unmaintained rate) + undercounting (possibly a large majority, possibly small) is probably React winning out
PS from your comment it sounds like you could be interested in Vue, specifically using Vue standalone without npm/webpack e.g. https://v3.vuejs.org/guide/installation.html#cdn
First, number of websites != number of platforms. If you go to the source of the number, they even point out as much:
> WordPress, which is used in more than 30% of sites, includes jQuery by default.
So right off the bat, you're looking at 50% or so, maybe plus a few for people who actually make a point to write jQuery + for wordpress specifically.
Secondly, that study has detection issues [0] that seem to not pick up a good deal of bundlers/etc, which makes it really hard to say how many of React/Vue sites are missed.
Thirdly, jQuery being used as a dependency of a library will still count it in that 83%. They show a few combination options specifically, and show it's at least 1.7% [1]. With others, say 2.5% in total. Think about how many bundlers hide React/Vue and how many common dependencies could use jQuery, and you're probably much higher.
Given all that, I'd bet that number is closer to 17% than 83%, though I'd wager around 33%.
Even with that 33% being jQuery without a framework or not being wordpress, you have to remember this is published. How many of those have had code significantly changed in the past 5 years? This is what's relevant in this context. All of this long winded nuance to say that I don't think "your average jQuery question is probably useful to many more people than your average React one" holds up, at least not like you might think that cited number shows. That's not to say it's irrelevant, just less relevant.
[0] https://github.com/AliasIO/wappalyzer/issues/2450
[1] https://almanac.httparchive.org/en/2020/javascript#framework...
The broader point is, we should be cognizant of our selection bias here. SPA frameworks are overrepresented on HN because we tend to be programmers building applications in the tech industry. But there are a ton of people who don't consider themselves "in tech" that still need to make a portfolio for their photos/figure out a WordPress plugin for their e-commerce site/etc.
I've been lambasted here in the past for saying this, but I'll say it again now and see if I get a different response; it's no longer helpful to search for "javascript" related questions and get mostly answers for jQuery. These days I'm able to solve a lot of problems just reading MDN, but sometimes I click on a Stack Overflow article and it turns out to be 12 answers that are all jQuery-specific even when the question itself doesn't call for it. jQuery isn't bad, but the world has changed around it and we can't keep pretending like everyone is using it for the same reasons we did back in 2011.
This not only does new developers a general disservice, but it can do a disservice to projects that have less-than-average momentum. For instance, I use Ember JS every day, and it's a framework that has really changed a lot since its inception, but you'd never know it if you looked up questions for it on Stack Overflow. The Ember questions on there are so woefully outdated that I believe it gives potential new users the complete wrong impression of it. There are outdated React questions on there as well, but at least there's enough inertia behind React that new activity helps overcome this to a degree. On the other hand, people almost certainly have given up on Ember because none of the Stack Overflow answers work at all. Sure, we could all submit updated answers, but they'll be below the fold and they will never be reselected as the accepted answer. There are other reasons why Ember has been in decline, but I do blame the mechanics of SO as a big detractor.
Preventing duplicate questions is fine, the overzealousness not withstanding, but if there's no mechanism to correct existing information as time goes on in a meaningful way, the only result can be rot.