I'd like to see a chart of desktop computer market share that people purchase for themselves.
One mom and pop machine shop I ordered from got tired of using USB drives to haul CAD files and machining instructions between systems so they started using Google Apps with Drive as the sharing mechanism. In order to do that, they had to hook up several 10 year old Windows XP machines to the internet and within weeks they got hit by the blaster worm or some other pre-SP1 virus. That cost them weeks of machine time on their older CNCs and hundreds of man hours doing incident reports for their bigger clients like the defense contractors. The situation in the clinical biotech companies I worked at was never that bad because of HIPPA compliance and more focus on networked services like lab databases but still atrocious. So much of our industrial infrastructure is built on a house of cards.
I can attest that academic biotech labs are still pretty atrocious, for the reasons you mention.
Windows XP (or super old OS X installs, pre 10.5) are pretty common on non-networked machines that function as appliances. It's not uncommon to hear about a machine controlling a $X00,000 device being compromised by malware that road in on a USB drive, despite the air gapping.
Sometimes I feel that it would be better for vendors to use a super minimal Linux distribution for each of these workstations that basically function as an appliance. Not only could the vendor reduce the attack surface for any potential malware exposure, but the one-off nature of the distro and small overall number of workstations would provide a minimal incentive for malware authors to target.
7 - 61%
10 - 28%
8 - 8%
XP - 1%
Vista - <1%Macbooks seem to have cornered the 18-25 female demographic for computers.
I see macs more among developers, but that's because I don't tend to hang around privileged rich kids that much these days, since I work for a living.
When I was at university though, the vast majority of computer science students were running either Linux or Windows. I think on the balance of it, it was mostly Windows, but the Linux users seemed to get better grades and had a better idea of what they were doing.
Macbooks were the computer of choice for the Arts and Commerce faculty students (most of whom, incidentally, did not have jobs).