Anyway, all this comes down to power, both in terms of market power and the social relations between manager and employee. The elite knowledge workers have something that is a critical factor of production for many businesses. Since this thing - knowledge, a form of fixed capital - exists inside the human mind and is extremely time-consuming to transfer, it has to be leased from the employees. Since it's in relatively short supply that commands a high price.
But that scarcity also converts into other forms of market power: the ability to set non-monetary conditions of sale on the knowledge.
This upsets the social relations of the office, because managers are used to being able to micromanage and physically surveil subordinates. The idea that an employee can set boundaries radically upsets American managers. Next people will be asking for holiday.
The reverse of this is of course at the very bottom end of the market: if your boss can change your shift pattern at the last minute, if you're on a so-called "zero hours" contract, then that's because you're deemed utterly replaceable and have no market power.