I wasn't completely serious about SAP, just meant to gesture to the the general direction of where I see commercial windows software. There are many corporate software vendors I deal with that sell windows software, for an example a suit of Office plugins that connects to SharePoint and do documents versioning.
Another area where I see windows desktop software, and I don't see it goes anywhere soon, is in industrial, medical and labs equipment control.
SAP can either be used as web based software and even thier "Windows" Software is mostly built using thier proprietary cross platform ABAP platform.