Because the biggest problems are the most expensive problems, and the most expensive problems require the deepest pockets, which belong to the government.
The subsidies for the Solyndra debacle are still viewed by many partisans as a reasonable price for a laudable attempt to do the right thing, instead of a massive waste of capital. Failure? What's that?
[1] http://blogs.wsj.com/ideas-market/2011/02/07/the-difficulty-...
[2] http://www.telegraph.co.uk/science/6694932/Have-we-discovere...