They're 100% explained by that, not just partially. At all of the top-rated restaurants in every city I've cooked in, all the chefs are buddies. It's very common for there to be a tacit agreement to just not pay more than $X, that way they can all keep labor costs down.
I know there have been some higher-profile suits filed against some famous and semi-famous chefs for unpaid wages/stolen tips (Mario Batali, Tom Douglas, Charlie Trotter, a few others), but it's hard to directly challenge collusion like this when it's very unofficial. And a quick way to end your career and get blacklisted from any other high end restaurant.
In a lot of the Michelin places, usually the chef will have a stake in it. To get investors behind them, they usually already have a name and bit of cachet and also worked for other Michelin-starred chefs. The ones I've worked at have varied from "celebrity chef, never actually in the kitchen, everything is actually created by the chef de cuisine and sous" to "micromanaging psycho" to "humble dude who just wants to make good food." So it varies - some manage every aspect of it, but usually there is a dedicated team for the front-of-house and the chef just does the creative side of the food, collaborating usually with his chef de cuisine and sous chefs. CDC and sous handle the day-to-day stuff like ordering, inventory, scheduling.
