If you replaced the contacts with a triac and replaced the switch mechanism with a thick bistable flexure, it would likely last centuries and have a BoM cost around $2.
I’ve had 2 switches fail over the last 2 years out of the ~40 switches installed in the house. One failed by welding itself closed and another failed by caving into the electrical box when I hit it too hard. Even though the 40 year life expectancy of a single switch sounds good, the reality is that one fails catastrophically every year. I’d love to get more reliable switches that last well over a century, but I’m not aware of anyone that measures this sort of thing.
I’ve had 2 switches fail over the last 2 years out of the ~40 switches installed in the house. One failed by welding itself closed and another failed by caving into the electrical box when I hit it too hard. Even though the 40 year life expectancy of a single switch sounds good, the reality is that one fails catastrophically every year. I’d love to get more reliable switches that last well over a century, but I’m not aware of anyone that measures this sort of thing.