Of course, Big Law works on a similar model. associates get billed out for far more than they make so it's in the interests of partners to generate lots of billable hours. And then it's basically up or out. Make partner (at which point, as you say, your job basically becomes sales to a non-trivial extent) or leave.
Law and consulting are different because more hours literally means more revenue. Banking is success fee driven. It's thus theoretically possible for hours to be reduced without impacting--or possibly, positively impacting--revenue.
Fair enough even if the end result is pretty much the same.
My understanding is that investment banking, which I made a very deliberate decision not to go into, throws associates at a whole lot of deal book production and proofreading that is only read by some other overworked associate.
Yea that's one of the worst things that really convinced me that the investment banking track was not for me: How utterly pointless the work was. You're spending 100 hours a week updating slide decks to use 14 point font instead of 12 point, and making the titles a different shade of blue. And it will all be read by....likely nobody, maybe someone who doesn't care what the font is. I'd rather grind as a software developer on a feature that never ships--at least there's creative output, and you're learning something.
Management consulting as well.