FLOOR PLAN............ or lack of one

Doing internet browsing of used RV's of all types, I am amazed how few sellers post a floor plan of their rig. If looking at any type of real estate - house, apartment, condo, etc, it is the first thing to appear. Now, assuming the seller has the complete model (is it a 32B or 32G?) I can usually find the floor plan online. Buy why the reluctance? Sure, they have to find a link or scan and then add to the listing. If you want to sell something, make it accomodating for the buyer. Dealers are better than private parties but still very few do. They often have tremendous well written ads with many, many photos(I've seen up to 200). But without a floor plan, it is often hard to see the forest for the trees. Your thoughts?