I'm beginning to see a very similar trend in Cataclysm now, compared to what we saw for the 2nd half of Wrath.
After doing the zone-quest chains (which might take you half a day per zone) there is very little reason to leave the capital cities (besides the currently very popular farming for mats). All faction reputations can be maxed out by grinding instances, which is also far more effective than doing the dailies. A lot of my fellow guild-members are already exalted with multiple Cataclysm factions.
There is no tedious "Sons of Hodir" grind in Cata that encourages people to get out into the world to pursue a "long-term" goal. Long grinds can be something positive too, as they give people something to work towards, and not only over a matter of days, but rather weeks.
I know part of the idea behind archaeology was to get people out into the word, but so far only a few people have caught on to it.
The new zone-design plays into that as well. While the new "streamlined" questing flows really well and is excellent from a story-telling and drama perspective, it takes a lot of mystery from the places. It feels like as soon as you've quested through the zone, you've seen and done everything there is to see and do. No real reason to come back (cept farm). Somehow Wrath managed to get me out into the world a lot more than Cataclysm seems to get people (in a month or two from now). But maybe that's largely due to the LFD.
Blizzard messed up when they scrapped the "Path of the Titans". If they wouldn't have scrapped that, it would have been an incentive for raiders or even PVPers to go level Archeology and see the old world. A lot of the people doing Archeology however are collectors or lore fans only.
The only thing worth leveling Archeology for in my opinion is the Sandstone Drake, but that's RNG.