[my123]

> Windows doesn't release a new version every year

Windows does nowadays (since Windows 10)... see the major (now yearly) updates.

The major Windows releases since the Win10 OG release: 1511, 1607 (available as LTSB for businesses, Server 2016), 1703, 1709 (first ARM64 release, for the desktop SKU), 1803, 1809 (available as LTSB for businesses, Server 2019), 1903, 2004, Iron (Server 2022, not shipped on desktop), 21H2 (Cobalt, corresponding to Windows 11 on desktop).

One aspect is that an older OS might have the headline vulnerabilities patched, but not architectural bugs or additional security hardening. Those aren't generally backported to older releases.