There's been a lot. Amazon generally avoids press, but they launch stuff that fails all the time. I'd say only 1/3 things they launch (or get really close to launching internally) is actually successful. Since they avoid press, people don't hear about things that fail. Their success rate has been higher with some AWS services, but if you could see their track record internally (basically things that make it to beta) vs. success 5 years later, it's probably under 30%.