I think we're talking about different things. I am talking about the groupset (the shifters, brake levers, brake calipers, derailleurs, crankset, bottom brack

I think we're talking about different things. I am talking about the groupset (the shifters, brake levers, brake calipers, derailleurs, crankset, bottom bracket, chain and cassette). There are indeed some wear items (chain; cassette, especially if the chain isn't replaced when worn; brake pads; brake rotors) but, apart from those, a looked-after quality groupset can last decades.