Does cloud make sense for everyone? When should you run your own infrastructure?

It's complicated.

AWS operating margins range anywhere from 25-30%. And that might continue to be strong, even if infrastructure becomes more commoditized (as AWS moves up the stack into higher margin services).

And cloud infrastructure costs as a percentage of revenue have never been higher for SaaS companies. The bottoms-up model is extremely effective for onboarding companies to cloud – it's extremely cheap to get started (in some cases, AWS will even give you up to $100,000 in credits as a startup). It only begins to become more expensive as a company matures.

A few observations: