[chess_horse_L]

It's not. Most of Unity games are mobile games, or indie games that don't require the GPU usage bloat Unreal has in order to achieve better graphics.

If Unreal was ever an option, developers would've been using it instead of Unity in the first place.

[catapart]

In case anyone cares, this commenter is absolutely incorrect; Unreal does support mobile development, and it obviously uses a more lithe package than its full GPU stack. Using only the UI objects, 2D is pretty simple and I haven't had any major package size issues. Using a 3D context to render 2D as planes in the scene, I can still get a package down around 70MB with optimizations left on the table. It's harder to work with 3D-as-2D, but that's why I use the UI system. It's robust.

I certainly like Unreal, myself, but I can't say it's an easy move from Unity to Unreal. That aside, one of the very first options you see is whether to scope your game for mobile or for "desktop", so I'm not sure why this commenter thinks that Unreal would not be an option for mobile development. It sucked before UE5, so maybe that's the hang up, but so did a lot of things.