It’s easy to see any move to squash Todd Philips Joker, if that in fact happened, as sour grapes, but there’s certainly more going on than that. There’s no good end to this scenario from Leto’s perspective. While Philips’ movie was always designed to be something separate from the DCEU characters, that minor detail was never going to matter. If Philips’ movie bombed, it would only mean stock in the Joker as a character would go down. If the movie was a hit, as it has now proven to be, then interest in The Joker goes up, but nobody is looking for Leto to reprise the role.
Article source: https://www.cinemablend.com/news/2482780/jared-leto-is-right-to-be-pissed-about-the-joker-situation