Don't forget that for FP jockeying, the Tier System and limitations to only one park for advanced FPs, mean that the competition is for just one FP per day. If you grab a FP for FEA, you can't also grab one for Soarin' or for any other Tier 1 in Epcot or for any other park for that day.
So, for each family group, the real competition is just for one very popular FP per day.
Also, these top tier E-Ticket rides are increasing their throughput. With the third tracks for Soarin' and TSMM, with FoP, SDD, MMRR, RotR, SW:SR, and everything else that's coming. There will be thousands of new FP slots available (what is the formula... 70% of the increased capacity for all these rides operating 10 hours a day?).
When the big three E's open up in DHS, I'm sure they'll all be Tier 1. And so, people at the 60 day mark can only grab one of them per day.
Also... while EMHs will be more crowded, they do have the effect of convincing some people not to go to the MK several times in one trip. It sorta pushes them away from the most crowded park.