The movie can't really bomb honestly because while it's targeted to a wider audience than just the game, it's not getting a theatrical release. Plus, with a story that doesn't need any outside context (like Advent Children which was purely for FFVII fans) it should even gain the attention of people who haven't played XV.
That being said, this movie will almost exclusively be viewed by gamers and Final Fantasy fans only, which isn't surprising, it's just another reason why the movie really can't "bomb" per-say.
As for if AC bombed, no, it didn't. Some people don't like AC because of the script and other things, but honestly it was really just meant for FFVII fans to enjoy and originally the project wasn't even going to be a film in the original conception. It's purely an action film for fans of VII and I think it does it very well. Even the small character arc that Cloud goes through during the movie was enjoyable seeing him reflect on his past mistakes and where he failed to save others and being able to save Tifa last minute was something I really enjoyed watching.
I think the movie will do fairly well and that people will enjoy it, but it's not going to be the next big movie of course... it's not trying to be though.