The upshot of this thread is if you're good, you keep getting the work. That's why names like Johnny Olson, Johnny Gilbert and Johnny Jacobs keep coming up. Back in the days of old time radio, it wasn't any different - there were a number of actors who kept showing up on show after show because they were good and flexible - Mel Blanc comes to mind as one of the busiest because of his versatility and range.
Hey, when Wink was doing all those Family Channel shows, wasn't Randy West the announcer on all of them?