Does anyone know why pricing of utilities like water and electricity doesn't follow a steep exponential curve? I.e. it gets really really expensive to have a 10

Does anyone know why pricing of utilities like water and electricity doesn't follow a steep exponential curve? I.e. it gets really really expensive to have a 10 acre estate fully watered during drought. Seems like either the excessive users will curb their usage (what we want) or they'll pay a huge amount that we can plow back into infrastructure. Or are these excessive users a drop in the bucket when it comes to total usage and we shouldn't even worry about them?