Chain is indeed a wear item. It costs tens of dollars to replace. $1000 groupsets simply don't deteriorate in the manner you describe. Source: I rode many th

Chain is indeed a wear item. It costs tens of dollars to replace. $1000 groupsets simply don't deteriorate in the manner you describe. Source: I rode many thousands of kilometers on my gravel/adventure bike, including a 1000km ride around Kenya (very dusty, rocky roads where there are roads). The only two groupset components I needed to replace on this 2016 bike so far were the derailleur hanger and a jockey wheel. The former got bent due to carelessness on my part and could have been straightened, but I chose to replace it for structural reasons. The bearing in the latter got a little sticky and so I replaced the jockey wheel. Each of the two parts cost the equivalent of US$15 here in the UK. I think this is a very long way from replacing the entire $1000 groupset, which was what the post I was replying to suggested.