I find it surprising that no OS yet comes with a distributed processing framework (i.e. a pluggable system to support things like Folding@Home) installed and running by default. I predict that it might be the norm in ten years or so; then we'll actually get the effect you mention, where anyone can rent processor time on "the InterVAC" (or at least "the MicrosoftVAC" and "the GNUVAC", if it doesn't get standardized.)