As one of the earliest and largest incumbents in the computer industry, when IBM, known as “Big Blue,” faced challenges from new manufacturers of computers in the 1960s and 70s, it is alleged that their salesmen, faced with the possibility of a customer buying a competitor’s system – say from RCA, Data General, Digital Equipment Corporation (DEC), Control Data Corporation (CDC), Scientific Data Systems (SDS/Xerox) – would deploy the deadly phrase “no one ever got fired for buying IBM,” usually successfully. Although IBM never appears to have actually used the phrase in advertising, its advertising strap lines did allude to it, as in: “At IBM, we sell a good night’s sleep.”
The phrase has come to be used as a cliché to describe how corporate bureaucracies tend to be risk averse and want to buy the solution or service their peers have also bought – that being ‘in the herd’ obviates criticism. It is used to describe how new entrants in technology and other industries (law, advertising, accounting) have to overcome the standing reputation of incumbents for not being a purchase choice that would be difficult to defend. It’s often also used to explain the preference for law and accounting departments in growing companies, as they become more bureaucratic, to tend to prefer only dealing with large established law firms or one of the ‘Big Four’ accounting firms.