"Why we shouldn't use jQuery anymore ?"
-> why ? if you want to revinvent the wheel and have the time to do it.

It's not the first time i hear that, usually from dev who don't understand what jQuery (or another) brings on the table.
So they go "vanillaJS" (like jQuery was written on cobol sigh)
and then they discover that they use it for things it was not needed
then that browser compatibility is a big issue
and finally that there's a way to do something that they could never have thought of.
But they don't like it anymore because "due to Jquery" they wrote spaghetti code... because of jQuery...
yea : "framework made me do it"

Some times later comes another framework...
and they start to use it because it's trendy, and years later they find that... maybe... they could have used "vanillaJS" in some places instead of the framework.

"i dont' fully understand why but i can do it better" syndrom