Microsoft, IT's biggest player, makes its money by selling stuff and it dabbles in services. They want you to buy Vista, Office 2007, CRM, the XBox, etc. On the side, they offer crummy overpriced support. The interesting thing about this is that the industry is moving more and more towards services. Red Hat, IBM, and Novell have pretty much bet their futures on OSS software in which they sell relatively little, but provide many services. Even Oracle, who have been selling Oracle for a long time, are getting into the services business with their recent "Unbreakable Linux" offering. Microsoft has resisted this, but even they have been forced to acknowledge the value of giving some software away (hence the "Express" editions of Visual Studio and SQL Server). This raises in an interesting question: what would happen if Microsoft moved towards a services oriented business model without moving towards open source? If any schnook could, legally, get on the internet and download Windows XP Home and Office 2007? Under this hypothetical model, Microsoft would sell business-oriented extensions to Windows and Office, but give fully featured versions away for any use, then charged for the support and custom editions/additions. What would happen? Would this be a good idea for them? It would partially diffuse a lot of the advantage behind switching to Linux.
Honestly, I think it would be hard but it may become fact some day. Even smaller software houses often make more money off of software maintenance than the software itself. As a plus, it is a lot less menacing then "leasing" software.