Do we know if the customers definitely pay the fees in full? One might imagine a large customer (like a pension fund) might be able to negotiate a discount, and the discount might not show up in the published returns, or something like that?
Fees are coming way down in the industry - very few shops can charge 2 and 20 these days. A flat fee of 1% is much more likely. Bill Ackman was a rockstar od the industry, so could get away with it for longer than most. Not any more.
Even in the old days, 2 and 20 was the starting point for a negotiation. If a client can bump up a firm's assets under management significantly, they have a lot of bargaining power.
Small to mid-size funds may not be able to get away with charging 2-20 but larger, more established funds still can regardless of size. Tudor was charging 4-23 on one of its funds. Not sure if that's still the case since they were down a bunch this past year.