I think that depends on how you think about levels. Why are commoners, farmers, nobles, etc... all completely suck? Why are only the players the exception?
It's for this reason that I've never thought about levels as actual "power". Levels to me mean only one thing-- Plot Connectedness.
The more connected to the Story you are... the more "power" (via game mechanics) you get by going up in level. PCs are the baseline examples of this, which is why they go up in level and thus seemingly become "more powerful" (via new and different game mechanics) because they get more and more connected to the Story. And any monsters and NPCs the PCs have to face as part of the Story also have more "plot connectedness", and thus are higher in level too. But that doesn't mean they are
actually more powerful than another monster or NPC when
you take away the game mechanics used to allow PCs to interact with them.
A random Town Guardsman that the PCs just walk past as they enter a town might only be Level 1, because there's no plot connection between the PCs and that guard. The guard doesn't need to have more, interesting, or diverse game mechanics connected to him, because the interaction between the guard and the PC will be virtually nil. And if by some chance there *is* an interaction... the PCs can knock the dude out with one punch because he's so low-level. He's not a part of the Story, their interaction is virtually meaningless, and thus he doesn't need more game mechanics than just what he gets for being Level 1. Whereas, the Town Guardsman who has kidnapped the Mayor's daughter (and whom the Mayor has sent the PCs on to find) gets bumped up to Level 7 so that the Story between the guard and the PC can actually be interesting
once the game mechanics get introduced.
But in terms of actual, literal, ability, skill and power of those two guardsmen (if you look at it from a top-down perspective)? They are most likely pretty on par with each other. They both have about the same training, they both have probably around the same amount of experience being a guard, they both have not done enough to get a better job elsewhere. They are both regular dudes with a job to do. But, because one guy interacts with the Story and the other guy doesn't... once guy is Level 7 while the other is Level 1.
For me, any other attempt to think of Levels as actual ability, power and skill is a futile exercise (in whatever edition or game you play) because invariably a higher level character has more and higher game mechanics at his disposal and thus ALL things he can do are extended way further than the lower level guy-- even things that have nothing to do with what they are actually trained to do.
When your Level 15 NPC is better dancer than your Level 1 NPC who is actually a trained dancer in the fiction simply because that's how the game mechanics shake the numbers out for these two NPCs... that tells you right there that Level doesn't mean a whole lot in terms of actual top-down ability.