I'd say the first things I've seen with the concept were probably stuff like Neverending Story, Peter Pan, Alice in Wonderland, and possibly random cartoons long before that.
For Anime, Fushigi Yugi and Escaflowne I both saw before SAO. Maybe Dual! Parallel Trouble too.
I tend to count stuff like .Hack and SAO as VR not isekai myself, as your body doesn't really get stronger in the real world, and usually your life in the real world isn't as affected either. For the ones who have that pining for a real adventure, I prefer permanent changes to "it was all a dream or might as well have been because their are no material changes."
Sometimes stories are like food. I can enjoy a finely crafted meal and it is very delicious. Sometimes though... junk food and unhealthy stuff just calls to you. You enjoy it for a bit but afterwards you admire it wasn't that great.
Some games, some manga, and some manhua especially fall under junk food for me, but I of course like reading full novels and the like too.