Anyone still running Windows XP probably knows why, and the reason is *NOT* MSIE 8 (or 7 or 6).
Redmond was never good at browsers and MSIE / Edge are at best "graphical download tools for a real web browser".
Windows XPsp3 is still the the version of Microsoft Windows with the least amount of serious security holes (no kidding!), it is still under active maintenance (just needs a registry key set to keep downloading patches), and earlier this year, Microsoft actually did ship an implmenetation of TLSv1.2 update for it: KB4019276
https://sockettools.com/kb/support-for-tls-1-2-on-windows-xp/
https://support.microsoft.com/kb/4019276