Software as Service

Bill Burnham has an excllent post about software as a service being the preferred way that IT organizations buy software today.  I agree with Bill completely.

But I wonder if web services and the ease of integration that Bill talks about in his post are going to bring more change to the enterprise software business in the coming years.  Will IT organizations move to lower cost lightweight web services and just integrate them in order to get the functionality they get from their hosted software vendors today?