Actually, that's not what happened. In fact the Congress has been implementing more wind subsidies because the market has been shrinking otherwise.
What happened to wind market was a combination of two things: back in 2008 debt markets and natural gas prices collapsed almost simultaneously. Debt markets have recovered, but natural gas prices have not. Today it's much cheaper to build natural gas power plants than it is to develop wind farms. Really, though, Pickens should've seen it coming 2 years ago (and privately he did - he's been trying to sell all those GE turbines for a while now).