The tulip mania never really resonated with me until I noticed that it take a year to "make" one. Corn takes 3 months. Houses 7+ months. It leaves a lot of worry time for people to get crazy and have large swings. The onion market which doesn't have a futures market, experiences large price swings based on yield. Futures markets help people lock in prices for which they need. This in stark contrast with a business that generates something regularly, eventually it settles in on a 10% profit when multiple players are allowed in.