Not unusual. Many orgs are still lagging on Win10 as well. They have contracts with things like cough anti-virus providers of ill repute cough and they cannot upgrade because these tools don't work.
We're rather fond of Windows 7, because it pretty much just works. (And nobody wants to deal with upgrading) A few of the handful of Win10 laptops have been headaches.
Funny you say that. Know what I'm doing right now?
Re-encoding MP4s to a slight variant of MP4 so that my demos are visible to Win7 installs. Because they flip out. Known issue, I'm told, but not fixable. Win7 is frozen!
You may not like Win10, but I think Win7 is a ghastly experience that is about as fun as bamboo shoots under one's nails (for developers). It has 0 affordances for modern software development EXCEPT misapplications of the Windows UI. Oh, also before I forget: old Win7 font rendering is substantially uglier than new Win10 font rendering! Critical stuff!
If "just works for email" is your criterion, it's a mistake not to use Chromebooks in the first place.
Well, it's not like you can expect Win7 to just doesn't magically support new file formats? Video is complicated and finicky, you'd be doing bullshit tasks like that for one reason or another
I agree with you that people should upgrade to Windows 10 as soon as they can. But I'm curious about what you mean by misapplications of the Windows UI.
"Lagging" is an interesting choice of words...