I agree with your statement the power top switches can be reconditioned back to operating condition. But the inside of yours look nothing like the original 69 switches I have.
Most times the brass contacts and rocker get tarnished and cleaning them gets the continuity back. Also the rocker can be bent over time and may need a little adjustment, as well as cleaning and lightly lubing the spring loaded plunger that moves the rocker.
One of the poor designs of this switch is the hinge point. The little side tabs can break off and render the switch non-op. I was able to drill a hole and insert a metal rod to provide a hinge point again. But then the spring loaded plunger does not work properly unless you shorten the spring the appropriate amount. It's a finicky thing, but can be done
