You can push much, much more volume and absolute impact through by running big merger integrations, digital transformation, and other large scale change projects at big companies.
It is basically a better business to become something like a premium Accenture, a "get stuff done" kind of consultancy. You can staff an army of junior people for a very very long time on those kinds of projects.
It's just not that easy to keep people staffed on 5-6 person teams solely on 8-12 week pure strategy engagements.
These kinds of projects are also the first discretionary spending yo get cut when times get tough.
If you're going to be focused on the pure strategy work, you'll probably want to stay really really small. We've seen some of this in investment banking with firms like Allen & Co or Qatalyst. Challenge is that consulting doesn't come with scalable monetization via success fees.
It's just not great business to be a boutique consultancy, I think.