This is often repeated but I don't believe this for a second. I have an 90s vehicle which is based on 60/70s technology. A switch for a fog light is like £10 on ebay for a replacement and I know I am not paying anywhere near cost i.e. I am being ripped off.
You think you’re being ripped off for a £10 fog light switch on a ~30 year old car?
That sounds like an incredible bargain to me.
Why do you think you should pay near cost? What’s the incentive for all the people who had to make, test, box, pack, move, finance, unpack, inventory, pick, box, label, and send it to you? I can’t imagine the price between £10 and free that you’d think wasn’t a rip-off for a part that probably sells well under a 100 units per year worldwide.
I'm pretty sure that simple switch is something directly in the circuit for the fog light, and there is a dedicated wire between the fog light, the switch, and the fuse box. And if its an old Jag, those wires flake out and have to be redone at great expense.
Compare this to the databus that is used in today's cars, it really isn't even a fair comparison on cost (you don't have to have 100 wires running through different places in your car, just one bus to 100 things and signal is separated from power).