Aren't the majority off mmos like this? FF11, WoW, even EQ. People like to feel improved. It doesn't really matter if those that come after you got short cuts. Sure there will be complaints but in the long run it doesn't truly diminish the feeling you had but now you have to work again to get it again. People chase the high. If it through crafting or dungeon. Eventually I imagine you will see a cycle of rotating between the two. Wow from what i understand is setup as "gateways" similar to DCUO where you need this gear to accomplish this to get that to move on to such and such.
So yes what does it matter is also like saying the game doesn't matter which it doesn't. People are engaging in a waste of time to...waste time and get some enjoyment. The fact it diminishes makes it addicting which is why they continue to chase it. Throwing logic at it won't change it.
I unfortunately am a puzzle guy I seek to solve things. So my high has no lasting effect at all since once I solved one I have to find another that is harder then the last but yet easy enough that I can perceive it as solvable since unsolvable puzzles would not give me a satisfaction. Collectors have it easy in that regard they need only know something is better, something is new, something is special for them to want it. Epeen or not people will do it and chase the high because the other option is stopping all together.