Massimo re Ferre’ with a long think-piece on VMware, Microsoft, market forces, value-add, and paradigm shifts in the data center: Will Microsoft sunset VMware? All his points are good, but I particularly like this one:

Maniacally focused: you need to consider
that for Microsoft this is one of the many battle-grounds. Windows
Virtualization is a line-item feature in a new OS release. This has
nothing to do with the fact that, for them, this is very important or
not. It remains a fact that their overall efforts will be diluted
across a number of markets that span from OS dominance to databases,
from mail systems to development tools etc etc. For VMware this is
"THE" market. They are laser focused to provide the best x86
virtualization experience and solutions. That’s what they do and they
can afford to run full steam towards that result. Whether they will
succeed is another matter but it’s important to notice.

And in his conclusion he invokes a paradigm shift coming in how we manage complexity in the data center. Massimo is particularly excited by Virtual Appliances (as am I), but 
his vision of the future data center isn’t dependent on that.

These are the reasons for which I don’t think Microsoft is going to sunset VMware. Clearly they will pose a challenge on them (a very tough one) but I don’t see VMware as being kicked out so easily. And the number one reason is because I really think that our Datacenters needs to be re-designed from the ground up. Let me quote myself: "This is a fascinating scenario and as you can imagine it involves more than just developing a hypervisor with a management interface: it involves creating a new culture on how we deal with IT, taking all the pieces apart and rebuild our datacenters in a much more efficient way". Now if we agree that Microsoft is making a lot of money out of this "legacy" model (this is a fact) but that we need to change it (the legacy model) to become more efficient anyway … do you think that Microsoft itself could be the agent of change in this case? If they are not pushed they will try to maintain the status-quo (well status-quo with license upgrades as new product versions come along). I remember 5 years ago I went to Microsoft asking them what they were doing about virtualization since this little company called VMware was having brilliant ideas on how to consolidate servers and they told me that they response to that was Itanium and Windows 2000 Datacenter.

See also the responses at the VMTN Forums.