Ask HN: Debunking the SV silly-money-for-silly-ideas myth

As a middle aged tech guy, I am sometimes asked by younger fellows why SV uses so much money for b2c ideas that would be deemed spent, foolish or unfeasible elsewhere. In other words, how can you get running big funds for another basic SaaS or copycat app or mechanical IoT equipment. The latest source for discussion was Juicero, something a local team over here, out of the SV, was thinking of a few years ago and had to drop because of absolutely no traction. My collaborative answer is it is something related with venture capital placing speculative bets in the hope of winning the unicorn lottery, sometimes independent of the substantial merit of the underlying project. I realise it is a bit consolatory and no one is satisfied. Better answers then?