Gmail drives Enterprise Apps adoption

Following Google's recent claims of increasing Apps adoption among enterprise customers, CIO Magazine has a snapshot of one company's transition to the platform as a frame for an article called "Why Enterprises Are Moving to Google Apps, Gmail."
It's no huge surprise that the second is driving the first; they aren't moving for the "Apps," they are moving for the mail. The impetus behind that is no surprise, either: cost and the reduction of complexity (which is really just a different kind of cost). I think if there is anything in the whole scenario that surprises me, it is the element that the recent announcment of Outlook support plays into this decision. On second thought, it shouldn't; people like things that are familiar, and Outlook is familiar, even if the more powerful aspects of the program are left to languish without the Exchange server backend they require.
Something else that jumped out at me was a quote from the IT director of the company in the case study, Brent Hoag of JohnsonDiversey. "E-mail is critical to our work, but we're trying to simplify IT." I often hear e-mail referred to in that fashion, as a mission critical system, but I also see exactly how it is typically used and the problems it causes and I question the assumption (which, incidentally, I have never seen proven, not in the same way that other critical operational support systems have to be ROI justified). If Gmail is causing CIOs to question the conventional wisdom of running in-house mail servers, I can't help but wonder: will Google Wave finally cause them to seriously question exactly what good e-mail provides and how those benefits might be more efficiently achieved by other means?