Don't forget that only ~1% of startups develop breakthrough products, because only ~1% of startups break through.
From an after-the-fact standpoint it's easy to point at the losers and say all kinds of nasty things about them. But since you can't reliably pick the winners of tomorrow, nor can the losers reliably pick themselves (they are usually both at different times) any sentiment towards failed startups being a waste is really just a misconception.