I respectfully disagree. Also, word to the wise, don't ever say that to an IT department during an interview. Counties and banks keep hardware 50 years old and maintain OSes that are decades old -- and many run on COBOL and various ancient, long-dead languages. Then, there's the product designers -- like boat hull manufacturers which use CAD-based systems that are easily 15 to 20 years old running on OSes almost just as old.
You want the latest and greatest libraries and functionality -- great. Good for you. Most organizations want to buy something and keep it 'til the wheels come off. Even with regular rotations for equipment, the old 5 year life cycle has turned into a 7 to 10 year one in most counties.
My photographer friends use Adobe Lightroom mostly, but some use Adobe CS 6 and will stay with it until their machine dies and it's impossible to re-install and activate the product. Most of them use Windows 7 and will gladly disconnect the Win 7 box from the network and transfer files by hand to keep it going without having to update to Windows 10 -- ever.
If you're selling a subscription model software, then one should poll the base to see whether or not it's worth supporting their respective OSes. If they've done that and have decided to nuke support for older OSes, then they should just stop offering the subscription license for the unsupported OSes. Let them get a notice -- hey, upgrade your box or your license will de-activate and we'll stop billing you.
That way, there's no half-hearted attempt at keeping the customer happy by allowing them to use unsupported software for a fee.