Parts availability is the real issue here, not just the throwaway mindset. Try finding a single chainring bolt at most shops now and you'll be lucky if they have your length in stock, so the path of least resistance becomes a whole new ring even for someone who wants to fix it. Add in that a lot of modern cranks use proprietary bolts or weird integrated designs and suddenly the coffee can approach doesn't even apply. I keep a jar but half the stuff in it fits nothing I own anymore, which is its own kind of sadness. The know-how isn't gone, the supply chain just quit supporting it.