AI spending is rising everywhere, but the power users are pulling away. a16z's Sarah Wang on the gap between the top 1% and everyone else: "You can think of AI spending rising generally across companies, but the power users, the most intensive users, are spending much, much more." "We looked at some YipitData for this, and if you look at median AI vendor spending in the top 1%, that's roughly eight times the level of the top 10%." "Anecdotally, even inside our own portfolio companies, which…