I'd say it would be unusual to have more than one or two faulty switches in your game.
If many are not registering in switch test, the problem might still be a short or possibly a connector issue and not the switches themselves.
Also you said the game was working ok before the problem occurred?
I wouldn't replace any more switches just yet, unless you are 100% sure they are faulty.
Do you have a multimeter to test the switches?
