For some reason you must be seeing more of the pictures of bikes that are for sale or copy/pasted pic's from the brands website. Most new bikes are sold without pedals and likely many used bikes that have other than plain pedals and are for sale will have the pedals removed as the seller likely will use those on their new bike. There are enough variations in the types clipless pedals that they'll likely be useless to the new owner if they have a different type of clipless pedal.

I don't know that I see a majority of bikes with or without pedals on the site. Maybe you can do a count for us of how many pics have pedals and how many don't. It'd be useful to sum it up by year posted and maybe if you do it by months, then we can see if there is some cycle they com in... no pun intended (I think).