Unfortunately, your hunch is proven wrong wrong wrong by statistics. Actually, in-house development fares worse than that (if you count ones that go over budget, over schedule, under scope, don't get used AND ones that get scrapped completely) and I don't think you're suggesting that the odds of an outsourced project are better?
Stats on that are everywhere. Some are here: http://www.codeanthem.com/blog/2010/04/how-to-save-the-softw...