> You will find that of the top 500 supercomputer sites in the world,
> not a single one runs either Windows or Mac OS X. Only 16 - just a
> hair over 3%, run something other than some obvious distribution of
> Linux.

I think there are better examples than HPC. How many of us actually
use any of these 500 top supercomputers? Very few of us.

Look around you, where do you see Windows, iOS, MacOS, and Linux?

Windows is mostly a niche operating system, its niche is desktop and
services which support desktop.

iOS is again a niche OS, phones and tablets.

MacOS is mostly in the same niche as Windows, but less so for services
which support desktop.

Linux, runs nearly everything else, but because that is not a desktop,
what most people consider a computer, it is invisible to them. You
need to give examples of these invisible things. Android. Smart TVs,
wireless access points, set top boxes, printers, in flight
entertainment systems, modern ATM machines, most web services, drones,
mail sorting machines, most electronic medical equipment, etc.

So anybody who wants to be involved in computers which is not the
niche of desktop, will be involved in Linux, and the communities
around Linux.

       Andrew