It’s been production ready for ages but that’s a nebulous distinction.

Different studios have very different needs for scaling their production. Blenders suitability varies greatly by the project and needs. For example, it’s used on Spiderverse for specific things but cannot scale to do the entire animation production yet.

Your second point about user generated content makes no sense imho. Games don’t use DCC files for runtime. They will have their own runtime formats that are generated during the build. Blender is just an unsuitable or suitable as any other DCC in that regard.