I think that If Booker T vs Stone Cold had happened on ppv, that would have helped. I think it ended up as a smackdown match or something.
For RVD, I think the wwe didn't have a long term plan for him and that really hurt. Plus 2002 saw a lot of wrestler debut and join the company so they were probably busy figuring out that but yeah RVD lost a lot of heat in 2002. I don't remember anything major happening until Kane in 2003.
Speaking of which i feel that Austin had lost a lot of momentum due to the Scott Hall feud, maybe that was because he was vetoing everything.
EDIT: I found this. Like what this the way they want to have these guys wrestle each other. All the promos post Invasion were great and this is what they have to show for it?
Stone Cold Steve Austin vs. Booker T - lumberjack Match
What were they building this towards?