Former and current drivers said the trend could be traced in large part to changes in cab leasing terms in the 1970s. With rules that now often require much of a long day’s work — a standard shift is 12 hours — just to cover the daily rental rate, there is far less latitude for students, performers or other young New Yorkers to drive cabs for part of the day as supplemental income.

“I went into this thinking it was a steppingstone to something,” said John McDonagh, 59, a cabby who was raised in Middle Village, Queens. But his more than 35 years as a taxi driver have led him to instead perceive his job as a springboard “to the end of my life.”

Another consequence of the lease changes: Taxi operators were once far more invested in the success of their cabbies.

“It was just a much better job,” said Tom Robbins, a journalist and author who drove a taxi in the 1970s. “When I had a good day, the boss had a good day. When I had a bad day, the boss had a bad day. Once leasing came in, the boss never had a bad day.”