In my view, your points do not counter the simple truth: Microsoft do not have a monopoly. We may not like that they stop the support, but the legal avenue of claiming they have a monopoly is a dead end.
Regarding your specific issues:
The majority of XP systems can easily be upgraded to later versions. In the company I work for, only approx 1% of the systems cannot use Win7 64 bit (still a significant number). For these, we use various workarounds and fixes:
- Connect the XP machines on closed networks, behind restricted firewalls, or not on a network at all. Much of the malware out there will need an internet connection to do any harm, so network restrictions will both prevent infection and reduce the impact of any infection.
- Then there are solutions like bit9 which (when properly configured) prevent unauthorized code from running on the system.
- Our company has had good success with Windows 8 32 bit. From what I have been told, most of the software which does not run on Windows 7 64 bit (our standard platform) will run on Windows 8 32 bit.