Has there ever been an analysis to see what is most likely to break on a rolling distribution? I have been using Arch for years, and have only had a couple of hardware related issues. If that is typical, rolling distributions may not even be an issue when the vendor has tight control over the product and can isolate hardware related packages in their own repository.
In my own experience, the hardware support that breaks is the GPU. For me, the GPU has broken occasionally (once every couple years) regardless of distribution, unless I'm using an Intel GPU or an older GPU with mainline support.
I'm sure that Valve is going to install a much smaller set of core software than a typical desktop, though.
