I think Solyndra by itself is not strong evidence of anything. Any big loan program will have big failures. The real question of efficacy is not "were there zero losers" but "were there enough winners in the portfolio to make up for the losers".
Furthermore, I think the case could be made that governments are partly responsible for solar's historic price decline. The manufacturers needed economies of scale and learning, and demand subsidized go by governments (Germany, USA, China, Spain, etc.) really helped accelerate those private sector advancements. I'm not really sure how to evaluate this narrative, but I wouldn't be surprised if there were some academic economists who have looked at it.