I've downloaded and printed the whole manual for action script 3 when I was an artist (I've always dabbled in programming), apparently you could create pretty robust web apps with XML. Never had the time to create one myself and as3 was dead soon after that, I think jQuery killed it.
It seems a little strange to accuse jquery. I think what actually "killed it" was modern HTML. Jquery was just an intermediate API that let you target modern browsers and IE without having duplicate/shim code to maintain yourself.
