In the good old days (at least according to company old-timers) the boss determined when the company needed additional workers. The boss would put an ad in the newspaper interview job applicants and pick the ones he or she liked. If the new hires did not work out they would simply be fired and the process would start over again. In big companies a personnel officer would do the hiring and firing. The point is that for much of the business history of the United States there were no rules regulations or laws that placed constraints on the hiring or firing process.