All of those platforms are HUGE and well worth the hassle.
I think Valve is trying to leverage the Steam Storefront into a full-fledged Platform. It is not quite there yet.
As such, they have invested a lot of effort into the compatibility layers, which allows gamedevs to support Steam Devices with no extra effort, or minimal effort, which is very important business vise.
As a gamedev, you essentially get a bonus platform for your game without extra dev effort!
I think Valve is trying to leverage the Steam Storefront into a full-fledged Platform. It is not quite there yet.
As such, they have invested a lot of effort into the compatibility layers, which allows gamedevs to support Steam Devices with no extra effort, or minimal effort, which is very important business vise.
As a gamedev, you essentially get a bonus platform for your game without extra dev effort!