This is blatantly false. Apple has always provided security fixes for the past 2–3 versions before the current one. At their current version release schedule, that means a given version will be supported for at least 3 years or so.

At the moment security updates cover versions 10.9+. The most recent security update for OS X v10.8.5 was in August (a bit over 3 years after the initial release of 10.8), and 10.9+ have had an additional 5 security updates after that.

You're pretty wrong.