Ever Increasing server resource requirements
The times where users are content with static websites ( or even basic dynamic sites) are passing by us. Now clients/users are demanding ever more complex web applications to drive their business. The resources required to run some of the more intricate web applications are only increasing.
Users want video; they want applications to collect their customers' information, they want a myriad of different functionality for processing vast quantities of data ( image, video and text ) from their customers and various portions of the web.
Servers are only getting beefier as well, but I have noticed a trend in requests for more complex applications and for applications that do some heavy processing of images and video. I believe as this trend continues, more and more clients will realize the need for a dedicated server, that a shared hosting environment cannot give the resources necessary to keep their complex applications running as fast as desired.