Thanks, I'm aware of that. All I was suggesting is that I think most non-commercial C of A type operators (ie private Cessna/Piper owners), given the choice, would be more than happy to save 75% of the cost of a new part by having one (identical) that didn't have a certificate of conformity.
I'm not suggesting that inferior or alternative manufacturer parts are used as substitutes, but there is a raft of identical hardware (made in the same factory) out there that can be sourced, albeit without the all-important 'yellow ticket'.
On the subject of alternative manufacturers, there are also lots of cases where it seems ludicrous that alternatives are not permitted too. Take interior plastics for example in a C172. It costs thousands to replace a whole set in an aircraft if one buys genuine Cessna ones, and one is obliged to do just that. However, other manufacturers churn them out for 20% of the cost and because they're not 'approved' on a C of A type, they can't be used. I'm not convinced that the aircraft in question is going to enter 'plummet mode' just because the panel and door trim plastic isn't genuine Cessna stock.
And the above example is a single one of hundreds that can be made.