The Flash failed because in a world where the public at large is painfully aware Ezra Miller is at best "troublingly weird" and at worst glaringly problematic, you didn't just double down on Ezra... you TRIPLED DOWN. Most folks didn't even wanna see him ONCE in the move let alone 3 different versions of him. And I'm pretty sure many people who saw the movie in theaters were only there for Michael Keaton's Batman.