He burned his bridges not just with Fox but every major and minor studio. He'll have trouble getting a good sized Indie to direct. He's proven with this to be unstable, unprofessional, untrustworthy and unable to take any responsibility for his own failings.
Unless a production is micro sized, desperate or he raises his own capital there aren't many in the business who are going to work with a director who will trash his own product on opening day and throw the people he works with and for under the bus in a scramble to salve his own ego.
All of this.
Studios interfering in films has been happening since there was a studio system. It's not new. It's something a new director should be prepared for, like a necessary hazing ritual. It sucks, but it's the reality.
Fact is, many of these "hazed" directors can still make a career. But in order to do so, you DO NOT do what Josh Trank did. Nobody's going to back Trank now that he's trashed his own movie publicly and went on a tirade online (if you believe the long posts on 4chan were from him) and aired all the dirty laundry. Not to mention the rumors of him being erratic and irresponsible on set. No studio is going to want to deal with that. Hence him being fired from Star Wars. Disney/Marvel is a well-oiled machine, they don't want to get involved in this kind of drama.
David Fincher is a smart man since he's not on social media. It's a very, very careful line they have to walk - directors, crew, and actors alike.
I would feel bad for Trank, but he's the same age I am and I had way more sense than he's showing when I was 10 years younger. He brought a lot of this upon himself. New directors have been chewed up and spit out by the studio system, he's not the first guy to experience it, and to act like he is is extremely immature. In fact, he had a model more than 20 years ago - the aforementioned David Fincher. After Alien 3, Fincher buckled down and went back to work doing commercials and music videos, then came back with a vengeance with Seven. And the rest is history.
That very easily could have been an option for Trank, but instead he chose to be an immature punk, act out, and whine about it for all the world to see. I'm embarrassed for him.