@TandyQ I've been watching behind the scenes and VFX breakdowns of movies since I was a kid and it is absolutely jaw dropping the advancements of VFX over the last 20 years. The original post is just bait.
@TandyQ It's 1000% the lighting. The actual background looks great and VFX artists can 100% make it look like it's fully part of the shot. This has to either be a stylistic choice or an (improperly) lit stage that the director wanted to change after it was shot.