Yeah, well shall we count the number of companies that launched on TechCrunch and then disappeared into oblivion as well? Arrington does not bring the rain, he is just standing behind you, pissing on your leg and saying "wow, did you see that dark cloud that just went by?"
Couldn't disagree more on his statement: "Never start a company just to start it. You start a company because you have an idea that you think will be great for some customer and great ideas are always worth doing"
IMHO the biggest reasons to start a company is just to start it. The biggest companies have started that way - most famously HP. Ideas are mostly incidental and most of the time the first ones rarely work out. The biggest ideas are not really that clear early on - Writely was only a great idea because it got acquired by Google.