As a counter-example, I recently read Twitter was built on Rails 6 months after it was released. Once the concept was proven out, and the production app was fai

As a counter-example, I recently read Twitter was built on Rails 6 months after it was released. Once the concept was proven out, and the production app was failing like crazy (fail whale everywhere) - they rewrote their entire stack in Scala/on the JVM. Now should have Twitter spent the first 6 months of their life building out the perfect infrastructure with proven tools spending the little money they had mainly on engineering or were the justified in pushing that technical debt down the road to focus on other things today. It seems to me, for most startups, that the marginal cost of building it "right" today is much higher than rewriting when you can/if you need to.