[Groxx]

Sure, as a follow-up they could do that.

That's (very clearly declared to be) not the goal of the author though.

[jayd16]

My point is that by separating the layers it does fulfill the declared goals but in a more portable way. As implemented, there could be hidden dependencies on the local file system or across game installs.

[reificator]

But it then prevents redistribution of the container images in a legal manner, because the game files themselves are still under copyright.