Re: 500 lb gorilla in the room
Microsoft is already at risk on the client side. We've been here before. I lived through the PC revolution and all the naysayers who said "real work" gets done on the mainframe or minicomputer (i.e. green screen). For those that say "real work" isn't done on the iPad, hogwash. It's a human interface problem, not the fact that "real work" cannot be done on the iPad. Someone sells a POS system for the iPad -- no, not just a simple Square payment device, a fully grown POS. Sure, it sticks an iPad in a frame attached to a cash drawer but that's the "human interface" issue. The iPad Air is dangerously close enough to having the power to do all that a laptop does. The only difference is the human interface and that's easily solved. Many companies now develop "mobile first" and guess what's first ... the iPad.
Regarding the enterprise, most folks could care less what runs HTTP JSON Web Services. Windows, Linux, Unix, Mainframe CICS, AS400. The only thing that matters is does it work and what does it cost.
Databases -- SQL Server has legs but in 10 years, will we care what the RDBMS "service" is that we use?
E-mail -- Exchange has legs but in 10 years, do we care whether or not our tablet e-mail/calendar app connects to Google, Yahoo, Lotus Notes, Exchange or Outlook.com?
Microsoft's enterprise data center penetration came from everyone using their client and the subsequent realization that the client did more and was easier to manage if they combined it with other MS products. By owning the client and the server, MS has been extremely successful. They may have already lost the client which allows others to dictate policy to server room. Customers and staff want their stuff to work. They don't care what it takes to make it work.
If Apple suddenly shifted their iPad Exchange compatibilities, would folks get rid of their iPad, get rid of Exchange or look for an app that made it work? It's pretty safe to say that they are not going to get rid of the iPad when other LOB apps only work with the iPad. They'll probably find an app. However, if that app works better with Google, you see where this goes... This same logic exists for why Windows has legs. So many LOB apps require Windows. Is there a tipping point at which many of those apps are rewritten for the iPad? Right now iPad uses Citrix to access desktop capabilities but if they can run those capabilities locally, why do they need to license all that Microsoft stuff?
Microsoft will lose their competitive edge if they lose the end-customer to other devices. They have to win it back or at least level the playing field by retaining a lot of it. Otherwise they risk becoming similar to IBM. However, IBM was primarily a hardware company. Microsoft is primarily a software company.