>>37073140It's a "failure" because it didn't live up to Lucario's success before it. Zoroark was intended as the villain to Luc's hero but lacked the stats and busted typing to match. Kids didn't latch onto it and the design was a bit too rooted in Japanese culture to take off worldwide as well.
Despite this, it has one of the most dedicated fanbases in all of Pokemon so Theater Fox at least has its niche.