XP is my main OS
I installed XP in 2006 and have the exact system that I installed in 2006 still running fast. I always Ghosted the system before installing new hardware just in case.
Huge amount of updates are required to get the system to do everything a Windows 7 will do out of the box, but then over 14 years you hardly notice.
If you choose decent Motherboards like SuperMicro – they are still supplying drivers for XP from the website.
https://www.supermicro.com/support/resources/resource_drivers.cfm
Likewise Nvidia and GeForce are supplying XP drivers.
It is mostly the software venders that limit the installation of their products.
For instance I still use Adobe Acrobat XI Pro, Adobe Photoshop CS6 and CyberLink PowerDirector 12. I am stuck with AutoCad 2012 and Revit 2013, but they work fine.
I use Office 2007, but over the last year started using Office 2016 on a remote Win 7 machine. So I can really use later software if needed in a windowed remote desktop.
I switched over to a copper base Dell 1737 with a dual core 2.8 as my Win 7 machine and it boots on lan from my main XP machine – so in effect is just like having another couple of CPU’s. Very useful when downloading as has different MAC and IP.
I think the people that Run XP as there main machine – probably do so because they have to.
I have certain programs and hardware that will not run on Win 7 or later. For instance SuperWriter32 and some proprietary engineering software. I was using a GA2000 plus for years it cost over £5000 and £500 per year to calibrate, but Geotechnical Instruments didn’t release drivers for Win 7 so in effect a lot of valuable hardware was made scrap. It still downloads and works on my XP and the company gave these away, as they eventually migrated to Win 7.