Take a look at the new features of Windows Server 8 Hyper-V. Now consider that these (and all of Hyper-V) are all built into your VM licensing and you don’t actually have to pay for them. Buying VMware is an additional cost.
IDC released their predictions for 2012 and #3 is:
2012 Will Be VMware’s Last Year as King of the Hill
To be fair, IDC has also previously claimed that Windows Phone would grab the #2 spot in the market, ahead of Apple *ahem*
But this is different. Hyper-V right now beats VMware on price, and when you try to reduce VMware pricing, 2008 R2 SP1 Hyper-V beats VMware on functionality. Windows Server 8 changes that field by dealing with the objections and by doing stuff that VMware doesn’t. And don’t forget that System Center (current and future) smack VMware’s “management” products around like a one-legged little person in a heavyweight MMA fight.
Queue the wailing and gnashing of teeth. I look forward to moderating the comments by VMware marketing 
IDC said Windows Phone would be #2 in the market by 2015. I wouldn’t dismiss that so easily.
Andreas, their progress, as expected has not been there. Nokia has not been the great saviour. MSFT marketing has under-performed. And sales have not improved. Actually, I thought I heard that Windows Phone market share has gone down.