old boards losing their "pop"

ok this was kind of discussed in the new boards thread, but id like to hear more about it. Do boards really lose their pop over time? i ride an 05 premier and ride it 3-4 times a week for the last two seasons. This season, i dont know what is goin on but it feels sluggish and i have no pop at all. i jumped on a friends new board and i had no issues. so its not my technique. could it really be that my core has broken down? i suppose its possible, since two years ago i warrantied a board for a delamination reason and the shop checked out the board and said i had an 8 inch crack through the core running long ways. im just really curious why its riding funny and if anyone has any input on the subject.