Nice analysis of firing pattern and its reason.  The major factor of rapid hiring and firing of startup is that the requirement of manpower fluctuates during its entire life cycle. Its very less during initial phase, grows during funding and hence expansion phase and then stabilize during stability phase. that why the rapid firing has become a common phenomenon in startups and hence raise  a concern on its credibility as career option. Also find the in depth analysis of startup firing phenomenon here:- http://www.fuckedupstartups.com/fs-analyser/startup-hiring-and-firing/