A friend's mother worked in a high-level consulting agency. Her time was billed out at $1000/hour, and she got less than 10% of that. Still a good wage, but she wasn't getting the lion's share of the fee.
Sometimes the only way to do such "expensive" work requires significant support. Things like their legal protection against liability, mandatory requirements to have X to do Y in a jurisdiction, and other sorts of things can really eat into the revenue of a small business or sole trader.
Exactly. The trick to billing $1000/hr is finding someone who'll pay it, and having the connections to get in front of them, and their trust that its $1000/hr well spent, which entails no small amount of theatrics on the part of a corporate shield.
In addition to what the others have said, it's also more difficult to strike out on your own due to 'having no replacement'. If a corp is reliant on you and you're part of a collective, then something happens to you, the collective will replace you. If you're on your own, a corp will be much more reticent, as the proverbial hit-by-a-bus scenario will leave them high and dry.
Disclaimer: this is only how I've had it described to me; I frequent the small end of town :)
I hear this all the time, but when I want to employ a lawyer they want $400/hr.