Why Michael Keaton Will Never Be Batman Again

https://www.youtube.com/watch?v=0rswQGcfc70

When it was first announced that Michael Keaton would be returning to the role of Batman after over 30 years, fan's were instantly excited. Though most were confused by the fact that Michael Keaton's Batman would be making his DCEU debut in 2023's The Flash. Why exactly was this Keaton's first shot at jumping back into Batman? And why would it be the last time we ever see Michael Keaton portray the Dark Knight?