I wouldn't take an overly simplistic fact like "Bitcoin has never failed" as proof of anything conclusive. First, "failed" is overly vague. If you mean it has never gone to zero, it's true but misleading in the sense that Bitcoin has not been without hiccups or controversies, not to mention crises. And don't forget all the exchanges that HAVE failed. Mt. Gox and Cryptsy are just two of them. There are others.

The spam attack has absolutely degraded the network. Most transactions are not affected, but many hundreds of thousands of transactions have been, and the result has been to push transaction fees through the roof. The average Bitcoin transaction fee is now over $5, where it used to be just pennies or fractions of a penny. Bitcoin is not nearly the perfect system your post seems to suggest. It's an interesting alternative to traditional banking transactions, but inferior in almost every way.