“When they retired from playing baseball, they had to work other jobs.”
As a coach and as a manager.
But he also ran a sporting goods store in downtown Pittsburgh, served as an Allegheny County deputy sheriff and baseball and basketball coach for the Carnegie Institute of Technology (now Carnegie Mellon University).
Walter Johnson managed in the minor leagues and major leagues (1929-1935), worked briefly as a Washington Senators radio announcer, was elected a Montgomery County commissioner, but otherwise had no success as a politician.
Babe Ruth wanted to manage, but got only a single season gig as a first base coach for the Brooklyn Dodgers. Thanks to his wife's careful money management, he did not have to work a paid job, but she sought out volunteer gigs for him to treat the depression he suffered as a result of separation from baseball.
So it all depends on which player you are talking about. Not all of them coached or managed, at least not full time.