Firing people is risky for the person potentially being fired, not for the owners of the firm. Growing and shrinking over time is part and parcel of running a consultancy. That's why you see it all the time, and I'll bet if you look closer at the ownership during layoffs you'll find that they very rarely miss a paycheck and usually escape unharmed.
The fact that it's an unpleasant reality doesn't make it any more risky than e.g. having to pay taxes.
The fact that it's an unpleasant reality doesn't make it any more risky than e.g. having to pay taxes.