Why is Twitter down again?

Why on earth is Twitter down again? They have experienced outages before, so shouldn't they have learned from them and fixed the problems that are causing outages? Or is the problem the fact that they are so dependent on Amazon, Google, and other flaky "service" companies? Maybe it is time that they build their own infrastructure. Maybe being in the infamous San Francisco Bay Area is an infrastructure negative rather than a plus. If they want to have offices in the Bay Area, fine, but locate all infrastructure where service providers are more reliable and they have more control. They have plenty of money, so is this a sign of negligent management, or what?

-- Jack Krupansky