No warranty necessary. Reputation alone would be enough. At least in those cases where people care about a reputation for longevity.

Paying more now for a longer lasting product depends on how much you discount the future (ie effectively your internal interest rate), and on how likely you'll think that you'll even want to use that gadged in the future. Eg the NES was probably ridiculously over-engineered for most people, since realistically they'd only need to not fall apart until you buy a SNES or Playstation.

People do, though; There is a thriving market for (heavy and expensive) stuff built to last a really long time. Obviously, if you want your product to be light and/or cheap, especially if (as in my case) your light product is supporting something very heavy, some sacrifices will have to be made.