I have worked in one of those companies. Most were lazy and did barely any work. They were there for a paycheck and it showed. Not everyone works in a mission driven startup where the employees are intrinsically motivated to contribute. Many are just free riders and hide under a middle manager hoping they don't get noticed. Such B teamers need to be weeded out quick.

Then I switched companies and everyone was motivated and hard working. The leader there hired better (less stragglers to begin with) and fired better (fired stragglers within 3 months).