What about that do you not understand? They keep RHEL as up to day as most businesses care to have it, the only thing really connecting RHEL 1 and RHEL 6 is the name, and there isn't much reason for that to wear out..
Unless maybe you are talking about Redhat the company, not RHEL? This article is about 10 years of RHEL.. Redhat has been around for nearly two decades now.
Red Hat distro was created in 1994, but in 2003 (~10 years ago) they created RHEL, merged vanilla Red Hat with Fedora, and shifted corporate strategy to RHEL.
Amusing they mark the start of the Fedora Project at the University of Hawaii, don't mention CentOS at all.
Unless maybe you are talking about Redhat the company, not RHEL? This article is about 10 years of RHEL.. Redhat has been around for nearly two decades now.