So did you do JS development back in 2006 without jQuery?
Then ExtJS, then a short stint with Ember and after that React.
I started with learning vanilla JS and doing my professional stuff with ExtJS.
But as you say, jQuery wasn't a requirement. I knew a few people who hated it with passion back then, they were all using MooTools. That's probably why I avoided it...
I only used ExtJS 4 and 4.1
I liked their API documentation and the xtypes that allowed for declarative Views. React reminded me of this later.
I read about those problems.
First they changed the license then the switch from 3 to 4.
This cost them many customers.
I started with 4, so I didn'T encounter these problems.