When you maintain systems long enough you realize that's a feature rather than a bug
Ask anyone outside of Valve or strange hobbies what packages actually 'make' SteamOS; they couldn't tell you. It's simply not their concern.
In fewer words: if you need/want to know the lifecycle, you'd know. The "by the way, they're a year old" message that started this thread is in bad faith. The Fedora release that equates to any EL derivative is comparatively ancient. It's fine.