There are sharper limits than you'd expect on how fast companies can grow. (Relevant: Ben & Jerry's vs Amazon: fast land grabs kill corporate culture, among other things; also that Robin Hanson(?) post I can't find about companies wanting to be bigger than they should.) You can borrow money, hiring is a bit harder, and assimilating new hires into your company just has to be slow, as well as restructuring management when everything gets bigger and you do more in parallel.