I got apps I made back in 1995 and 1996 for 32bit NT that still work on 64bit Windows 10.
The only thing these places do is to push the issue ahead and only make it worse. There is no going back in time, only forward. If your apps dont work on anything above XP. Then you need to spend money on fixing that issue, instead of paying out the nose to MS to extend XP support in small bits. But for most of them there is no software issues at all. Its just because some "IT" people have been sitting on their hands for too long instead of doing what they are payed to do.
The main issue tend to be evolving around the change of state rather than anything else. Its a large jump skill and understanding wise to go from XP/2003 to Vista/2008 and up in the enterprise. While going something like Vista/2008 to Windows 10/2012R2 is pretty straight forward and trivial in compare. Not to mention some newer hardware cant even run XP at all. Since no drivers simply exist.
They all got leasing type deals, so upgrade on the OS and Office part etc is free for them.
In case of some of them. Its not just XP. Its also Windows 2003 Server, Exchange 2003, Office 2003 and so on. Its no surprise they get hacked left and right and fight with incompatibilities with newer formats and technology every day.