I think things are going to slow down drastically from now on actually...
The massive leaps in technology have plateau'd, so to speak...I think future models will have some very minor tweaks with regards mechanical advances - the major steps forward will be issued as firmware updates...and you don't need new bodies to do that...
We've got so used to seeing new cameras every two years or so, with sub-model upgrades every 12 or 18 months...
Remember in pre-film days, Canon and Nikon only released new Pro cameras every ten years or so...
I think we'll soon be back to that kind of advance...maybe 5-yearly upgrades...