It was pretty rare for a TV to last long enough to need a new picture tube.
The damn things had two or three dozen vacuum tubes, which were constantly burning out.
The coup de grace was usually when the tuner went bad, and a newer, bigger screen model was in the stores.
We have it good now.
You have to think up an excuse to get rid of a TV, and they're cheap - it wasn't unusual to pay a month's salary for those old black-and-white sets.