I have 35 years in I.T. and made my living with Microsoft, Unix (HP, Solaris, AIX) Linux and Mainframe OS' over the years. In the past five years I've been somewhat of a Linux proponent/bigot.
In the org that I work in (a large multi-national bank) less than 5% of our desktops are Linux. 5% are Mac and the remaining 90% are Windows.
In the Server space, well over 60% are RedHat Enterprise Linux, 5% are Solaris/AIX and the remainder are Windows. Yes we have a Mainframe, I don't count that as a "server." It's a very large Batch Processing environment that stands on its own.
So I'm a little confused where you come up with that 30% Linux Desktop total. Is that the environment you personally work in, or is that some industry metric I've not seen yet? (A link would be helpful if it's an industry metric.)
Hold on and give me a bit... I ran across that a couple weeks ago, so let me track it down again.
It was explaining that because MS is now embracing and trying to commandeer Linux the actual usage has doubled in reality as a desktop by other brand names.
The others speak for themselves as fact when discussing linux web hosting, It is all now Linux Apache. Amazon AWS... Linux. Google... their own linux version. You and your own servers. And appliance/robotics firmware. The list goes on and on.
The only place left That is not Linux dominated is the desktop because of fear and the ignoranance. They do not know yet what peace of mind and freedom is truly available...
But once you do there is no going back unless someone else forces you to, like work.