An observation made on wipers on cars

At Changi Village yesterday, I started to notice something interesting at least for myself. An observation was made.

I observed all hatchback cars and vans have wipers installed at the back but sedan cars do not have the back wipers. The only reason I could think of as to why sedan cars do not have them could be due to the design of sedan cars that limits the wiring. Since the cost of installation of back wipers could be small and it is good-to-have, this could explain why hatchback cars and vans have them.

Just my guess.