I'd say minimum $150 for a skid mulcher and go up from there. The $100/hr guy won't be around long if he's operating a decent machine. Unless he's a mechanic he won't be able to afford to fix their machines when they break at $90-$100/hr shop prices and $100 teeth.
It could be that apples and oranges are not being compared. Some guy running an old style tushhogg that he bought for $6k and is missing teeth and guards could be running it on an old machine with 30 gpm with glass door or no door and actually make money at $100/hr. but he won't be too productive in that setup unless it's really small stuff.
I knew a guy who had an old tushhogg and i noticed he had no cutting teeth on the back wall of his mulcher. I asked him about it and he didn't know they were supposed to be there so there was nothing to recut the material. His drum was also missing teeth.
He was charging $100/hr, no insurance, no tax permit and hauled an over 26k rig without a CDL. Can't compete with that so I don't try.