The trends of Google search doesn't imply anything by itself, just that less people search Google for jQuery than React. Which isn't entirely surprising in my view - people use search engines to learn about something they're unfamiliar with. That doesn't necessarily correlate with increased usage. I've searched for React (although not on Google) but never used it.
It wouldn't be too much work to understand a bit more about the comparative usage. Looking at recent commits of projects on GitHub would be a good start, but also skewed towards open source projects which doesn't represent all actual usage of course.
Another way would be to look through historic changes to websites to see if there's any changes to the source. It'd be a bit complicated because content changes don't necessarily mean anyone is touching jQuery or React pieces.
This also ignores any sort of private usage, which you won't get any reliable data on, and may represent a significant amount of actual usage.
At the end of the day, there's only so much accurate data available to make accurate conclusions about usage of software libraries that don't phone home. The best data available, as far as I'm concerned, is what I posted earlier - and it's still not perfect and doesn't support any claims other than what the data shows.
As a side note, I don't have any dog in this race. I do think it's interesting to get a better understanding of what pieces of software are being used, by whom, in what amount, etc. but it's difficult.
No, you see the trends. You see that people have been looking less and less for jQuery and more and more for React.
But React hasn't reached the height of jQuery at its peak.
I would not be surprised if you're right in your assertion of what's used more for new projects. I still don't think the evidence you provided is enough to be so certain.
If I want to look up documentation for jQuery, I don't google the term "jquery" to find their docs. I just go straight to the docs directly. For a lot of situations, people's IDEs do enough work to not google something.
But that wouldn't still explain why searches for the term has decreased.
Besides, people in general do look up to the online documentation or links to the documentation from stack overflow.
It wouldn't be too much work to understand a bit more about the comparative usage. Looking at recent commits of projects on GitHub would be a good start, but also skewed towards open source projects which doesn't represent all actual usage of course.
Another way would be to look through historic changes to websites to see if there's any changes to the source. It'd be a bit complicated because content changes don't necessarily mean anyone is touching jQuery or React pieces.
This also ignores any sort of private usage, which you won't get any reliable data on, and may represent a significant amount of actual usage.
At the end of the day, there's only so much accurate data available to make accurate conclusions about usage of software libraries that don't phone home. The best data available, as far as I'm concerned, is what I posted earlier - and it's still not perfect and doesn't support any claims other than what the data shows.
As a side note, I don't have any dog in this race. I do think it's interesting to get a better understanding of what pieces of software are being used, by whom, in what amount, etc. but it's difficult.