Consumers are fickle, and you have to be on top of the latest trends in GUI, service, products, business models.
Corporate customers tend to be stickier, and more resistant to change.
The A/G/A/F foursome are geared for consumers, and are suitably nimble. The others you listed aren't. The worst thing a company can do is try to be perfect for both types of customers.
So lets take, for example, ORCL.
From 2000 till today, ORCL become the clear leader in enterprise: they acquired PeopleSoft, Siebel, BEA, Sun, etc.
On the other hand, MSFT position in enterprise space is in much weaker position comparing to competitors such as ORCL. Enterprises will replace their Windows with tablets, but I don't see them replacing Oracle Database or Oracle Applications (and Siebel and PeopleSoft apps are not so bad).
So Balmer gets B- for his enterprise work. Larry, on the other hand, gets A+.
Microsoft, however, have three products that will ensure their continued profitability - Excel, Exchange and (probably most importantly), Active Directory. This is over and above their insanely cohesive ecosystem, from SCCM all the way to Dynamics.
Active Directory is so critical because of the vast amount of legacy code that depends on it. Want to guess how many fortune 500 companies rely on AD?
 Nothing is guaranteed so yes, unless they evolve as the environment they generate value for inevitably evolves, they'll go.
Fast forward to 2013 ... what do you see? Did Ballmer really improve Microsoft position in enterprise comparing to Oracle and other competitors?
Every sizable company already has these things installed. Smaller and new companies may choose to spend their dollars elsewhere and that's a change of events for Microsoft. Projects that previously would go on Sharepoint are now done less expensively with cloud services, for example.
In tech, growth is in consumer, and with consumer tech drifting in to the enterprise, even enterprise IT spending may not go to Microsoft.
really? What can you do on your tablet in enterprises? You can have them only as an additional device. They don't even have any port where you can plugin something. And, you will have your tablets interact with whom?
At the end of the day, you need real machine running full blown OS to get shit done and not devices meant for playing with those face painting apps.
Given that there are already enterprise users out there today on Android and iOS devices, this is a pretty bold claim. (And you can, in fact, plug things into tablets with both operating systems - they have USB support.)
These are not all being deployed as "secondary devices" - in many cases companies deploy them because they're cheaper to deploy and maintain than a laptop, which only makes sense if you're not also providing a laptop to the user.
Having companies run solely on laptops or tablets has nothing to do with whether or not there are enterprise tablet deployments. Your logic is flawed.
Net impact on Microsoft's bottom line: zero.
google now says you interact with the tablet by voice, and you watch the screen with your eyes. Now, tablets can even derive events from looking at your face (samsung you look away video stops).
Noticed you don't need a mouse with a tablet?
Oh, the software will have to be rewritten, no doubt, but since most of the software is interface anyway...
Is that true?
Microsoft's ActiveDirectory, Exchange, and SharePoint are every where.
Perhaps they have different parts of "enterprise" pie.
In last 10 years, I have visited 100s of enterprise data centers and seen the transformation from primarily UNIX (non-Linux) and Windows server to Linux. Today I rarely come across UNIX and come across shrinking base of Windows servers. Ten years ago, I saw shops exclusively being either UNIX or Windows. Today shops are either Linux or a combination of Windows and Linux. In Enterprise OS market, Linux ate UNIX for lunch and now nibbling at Windows for dinner.
Active Directory and Exchange are much more popular because of its utility with windows workstation managements and user familiarity with PC and Outlook. With the acceptance of BYOD, thanks primarily due to iPhone and iPad, the MSFT hold on workstation side has started to be impacted.
Sharepount is not that much popular except in dominantly Windows server shops.
Most of the money is made on Windows Server licenses and many of these things get thrown in.
os, sql server, office/exchange.
Everything else is tiddly winks.
And most if not all of them have some kind of Office Document viewer and basic levels of editor, either built in, shipped with, or available as an app.
And how is Samba, a clone of Windows SMB file shares, going to help anything mobile?