Binary hotel shower controls

Why is it that so many hotel showers only have on or off as flow rate options?  So many have the single axis leaver/knob that you turn to bring the cold water to full flow and then add hot water, with the only other controls are tap/shower and drain/stopper. Sometimes the pressure is so high that the water is feeling over harsh. Sometimes the flow is higher than the drain can handle and you end up standing in water over your ankles even for a 5 minute shower even with the drain fully open. 
A) This prevents many from having their preferred shower rate that they are likely used to at home.
B) This causes waste of resources in both energy(which cost is increasing) to heat water as well as the water itself that is becoming a constrained resource in many places.
It feels like the hotel industry thinks we are so dumb that we can't manage the controls in the shower that most of us handle without issue at a sink.

I really treasure those hotels that have the dual axial like so many have for their sink taps with flow rate separate from temperature selection.  This does factor into my hotel choice, and I do let them know this I as I go (both positive where they get it right, and negative when they flood me out).