We have three children-- 13, 7 and 2. We have traveled to WDW since the oldest was 4. We do not do strollers for children past the 4th birthday. Ever. When I see a healthy 6, 7 or even older child being pushed about like a little prince, I do not think the parent is really serving the best interests of the child.
IMO, children should get tired from a day of adventure! Also, I think a healthy child that cannot comfortably walk, play, ride for several hours should have their overall fitness evaluated by their pediatrician.
It may be that we approach the parks differently than others-- we don't typically stay from opening to closing--instead we will arrive at opening, tour for several hours and then take a sit down break (lunch or snack in some air conditioned spot), tour another hour or two and then take a break at the hotel or see sit down shows.
And, although it is convenient to stash things in the stroller, it is a big pain to take the stroller on buses, trains, etc. Not to mention relocate it after CM repark it throughout the day.