What rubbish. XP usage had nothing to do with WannaCry.
"The reference to Windows XP is an uncomfortable reminder that the WannaCry attack that hit the NHS..."
WannaCry crashed on XP but not on 7. What bit the NHS (and Telefonica and others), as proven by the Shodan search engine, was their propensity for either hanging servers directly on the Internet or by intentionally exposing the TCP 139 and TCP 445 file sharing ports directly on the Internet and available to the entire world.
Negligence and incompetence cannot be fixed by changing the desktop operating system.