The question, Linux vs Windows is not about cost, it's not about features, it's not about performance, it's not about cloud readiness or anything like this.....
It boils down to one simple thing, control of your business
Which OS do you thing Google employs in their server park? Guess once guys, it does not come from Redmond.....
As far as I know there's not one single Windows server there, simply because they just can't afford it, when I say this it's not about money, but they can't afford not to have control.
They gotta have control on time-to-market
So if Google is rolling out a new feature that mandates a change in the operating system kernel, windows is tu-tu, because then they will have to ask Microsoft for this and wait a couple of years and when the feature is there and they can finally build the services.... it's just too late and Google loses business
With an open source model they can get the best developers there is and build what they want in weeks or months into the OS and service layers and beat everyone with this new feature set. This is why Linux and opensource models is a killer for bigger companies that wants to have control.
That's why Linux will go on-and-on-and-on..... Windows future may be more unsecure, though
I'm not saying this because I dislike windows server 2008/2012/2012r2 are insanely good server operating systems but Linux has better models and better future proofing, it'e just so simple as that........
If you want your business to survive you just can't ignore Linus
You're the man Linus!