First read post below.
... then again, endurance, to be able to keep going without getting pumped, is an acquired ability much in the same way as power, so why should power have any kind exclusive superiority when it comes to difficulty or grades?
I guess, we simply have to accept there are different kinds of routes, and just because you can climb one kind of route of a certain grade, it doesn't mean you can climb one of a different kind.
Most would agree it's easier to onsight a long endurance 8a compared to a short one. Nothing strange about that.