Royal Flushometer Failure

One of the differences between my apartment and most places I've lived is that in the bathroom the toilet uses a flushometer rather than the tank usual in private residences. This morning when I went to flush the thing first would not work and then allowed the water to flow until I figured out how to close the 'control stop' to shut the thing off. Learn something new every day and all that (The particular model is a Sloan Royal Flushometer and the internet supplied me with the assurance to turn the little screw thingy with worry that I was going to cause a worse problem).

It did make me wonder why different types of hardware are selected though. I know that to work the flushometer type need bigger pipes, but that should cost more money. Does the use of the type in commercial settings indicate that they make it more expensive to install but less expensive to operate? Certainly in rural settings the water pressure might be insufficient for the flushometer type to work, but why are they not more widely used in cities?