My experience was 25 years ago, but back then we analysts and consultants were making around 50-60K and they were charging clients 5-15 times that when we were staffed. So I'm sure having a good buffer of people waiting and ready to go was well worth it.

Even during the dotcom crash, they didn't lay anyone off IIRC. Instead they offered up to a couple years unpaid leave with benefits and guarantees of a job afterwards.