I heard it said "they" can make a light bulb that will last 100 years and not burn out. But if "they" did, everyone would buy 1 bulb and never have to buy another. The company making them would be out of business after everyone bought their first bulb because there would never be any repeat business.
So you know, they make 'em cheap so you have to replace them. It guarantees repeat business and keeps "them" in business.
FYI, I've never had to replace a refer in any of my RVs. (hope I never do either).