They deadass killed of an entire ****ing movie that was almost finished but thought THIS was theater worthy???
Those ****ers actually hate art and don't even bother hiding it
As far as Batgirl is concerned, I'm pretty sure it was cancelled as a result of the sheer state of disarray that DC's movies were in.
By my understanding, the original plan for the Flash was to remove Henry Cavill's Superman and Ben Affleck's Batman due to whatever changes Barry made to the timeline, which also somehow resulted in Sasha Calle's Supergirl and Michael Keaton's Batman being brought to the main timeline. (Ben Affleck seemed to have lost interest in playing Batman outside of cameos, though I'm not sure why they wanted Henry Cavill out - maybe him being tied to such a divisive series of Superman movies was enough, but they're seemingly keeping Ezra Miller on board despite everything that they've done)
Batgirl was seemingly being made in this context, with a semi-retired Batman and no Batfamily.
Then, the Rock seemingly attempted to take over the DC movie brand, placing himself and Henry Cavill's Superman at the center of it and dedicating not one but two movies (Black Adam and the Super-Pets movie) to set up the ultimate showdown of ultimate destiny between Black Adam and Superman. (Shazam was just kind of ignored for whatever reason) This was seemingly dependent on Black Adam being this huge box office success, which it wasn't. (and he also seemingly caused issues with Shazam 2's development on top of that) During this time, it seemed like Ben Affleck's Batman and Henry Cavill's Superman were coming back in some capacity - maybe the concept of the Batgirl movie could have worked in that context, but it would presumably require some reshoots. (I don't know how major of a role Batman had in that movie)
However, James Gunn became the co-CEO of DC's movie division, and the portrayal of Batman that he's going for (younger, with the Batfamily present) would have made the premise of Batgirl pretty much impossible.
Hopefully Leslie Grace appears in Batman: The Brave and the Bold as Batgirl (they're bringing in Batfamily members aside from Bruce, Damian, and Alfred - not sure who, but I'm willing to bet money that Nightwing makes an appearance, and I could see them bringing in Batgirl), but honestly, I'm just looking forward to the slate being wiped clean, DC getting a fresh start, and people actually having a plan for DC's movies. (it felt like they were accepting every single idea pitched to them at one point, no matter how ridiculous it might be - I would have loved to see a New Gods movie, but a movie based on The Trench, the ravenous barely-sentient fish-people from Aquaman, was in the works at one point for some baffling reason)
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I apologize for the rambling history of DC's recent decisions; I really want them to do well (I figure a rising tide lifts all ships, and I want to be more familiar with DC characters outside of Batman, Superman, Wonder Woman, and the Flash), and it's frustrating to see them repeatedly screw up some straightforward concepts. (I really wish Henry Cavill got to portray an optimistic/hopeful Superman, but Zack Snyder's default tone seems to be "gritty and edgy" - the theatrical cut of Justice League was the closest that we got. Also, the Flash's first movie being Flashpoint, and it seemingly having no involvement from Reverse Flash, seems like an odd choice)
(EDIT: I might have the timing wrong; Batgirl was cancelled in August 2022, while Black Adam released/underperformed in October 2022. Maybe by that point, WB was already assuming that it would be a huge success and that Ben Affleck would be back as Batman?)