"ignoring the cause of these things - which are that XP has a far weaker security model than Vista onwards which is really what causes people and processes to need to be admin by default."
No, the problem is a legacy one that MS allowed, and in some cases encouraged, bad security practice so they ended up with an OS that could not be properly secured because the software for it assumed all sorts of privileges that were removed by Vista and later to make things better.
I have at least one package that I can't run on XP without admin, or on later, because it needs to modify registry keys (now secured) for f-all reason.
Do I change OS and pay ~£1k for the latest version (and also change code using it), or so I run XP in a VM just for that job?
Yes, Windows 7 is a whole lot better OS than XP, but that is not going to make up for the sort of business legacy that is the reason folk use Windows in the first place.