From my perspective as someone who is both getting into gaming on Linux and also not much of a power user, Arch would have to make the installation and maintenance process a lot simpler to attract more people, and I’m not sure that’s something they actually want to do.
Looking at the official Arch installation guide, the average gamer may be overwhelmed by the process here, especially if they’re not comfortable with the terminal. Something like Linux Mint, on the other hand, has a built-in GUI installer with reasonable partitioning defaults, and it comes packaged with stuff like an app manger and update manager, something that will feel much more familiar to someone coming from windows.