It's scalable for the partners at Skadden (and similar service firms) to trade time for money because the time they trade is that of other people (viz., associates, and/or analysts at investment banks) who put in prodigious hours in the hope of becoming partners themselves someday in the distant future.
Sure. That's how you scale a professional services organization.
Later
You fleshed this comment out, which is great, but I want to be careful to say I'm not endorsing the business model of wringing hours out of people's speculative hope that they'll reach the top of the pyramid. We don't have "work 60 hours a week and make partner" model, for instance.
But the general principle of developing and refining skills to the point where they enable you to ramp up new people and deploy all your people more effectively is a good one that works in a variety of different cases.
Tech is myopic (extremely) about professional services; many of the largest firms in our economy are effectively scaled-up professional services companies.
Agree that tech is myopic... or perhaps it's just a segment of tech - there are a lot of tech people working happily for those large PS firms you mention.
I'm in public accounting. We just arbitrarily raise our rates. At the end of the day it depends on what the partners are selling. Audit work has kind of stopped growing. Consulting could grow but all these public accounting firms are fairly risk averse as well.