Not to be nitpicking, but parent didn't say it was a measure of time :-)
"Light years ahead" is a common expression meaning "much more advanced".
And there's nothing that says it refers to time (except if we insist on the idea that technology advances with time, so every related analogy must refer to time).
But as an analogy it just as well means "it's much further ahead", as if we were speaking of a race.
