No, not really. My point was that the reason the game makes level advancement relatively quick is to keep the players interested in their characters by giving them bennies every couple of sessions by leveling up. If the game withheld level up to a much longer number of encounters (and thus real-world sessions because you can usually only get through a certain number of encounters each time you sit down to play)... it runs the risk of making the game boring to a larger number of players in the middle of the populace. Because they've all been kind of taught over the years to expect more character leveling as a reward system. Even when that leveling doesn't particularly match the "reality" of how the game world evolves.
All the World of Warcraft players out there know exactly what I'm talking about-- how for some ridiculous reason you have 110th level bears. The same bears that are level 10 in one part of Azeroth are 110 on another, not because the in-game world's "reality" has a reason for there to be some uber-powerful bears out there... but just merely because it used character advancement as a way to keep players interested in continually playing the game and thus they needed to make level 110 bears to give those characters something to fight in the game.
And D&D is the same way in terms of not having the default game experience necessarily match the "reality" a particular game world might be set up as. Where a character could gain 20 levels of power in the matter of "in-game" weeks, in order to keep the out-of-game player interested in continuing to play over however many weeks, months, years the game goes on for. And you either just accept that as a fait accompli for how the games themselves work... or you make any number of revisions to how the default game is run to try and better equalize the out-of-game player experience to the in-game character experience and evolution to the world around them.