I looked it up because I was curious. [1] Apples to apples it looks like Windows "extended support" is closer to RHEL "Production Phase 3" support (not to be confused with RHEL's "extended support" which is vaguely "we'll keep the wikis lit and maybe answer if you hear ghosts"), so by that measure RHEL 5 ended "Phase 3" support in March of this year. With Windows 7 getting another 3 years of "Phase 3" support it looks about like RHEL and Windows' timeframes are very similar in this case.

[1] https://access.redhat.com/support/policy/updates/errata/