Not necessarily. I don't go from zero to product till I have verified that there's a need for the product. I try to fail fast before developing the product. By

Not necessarily. I don't go from zero to product till I have verified that there's a need for the product. I try to fail fast before developing the product. By the time I'm developing the product, I'm fairly certain it's not going to fail immediately after launch. Oh, and once you've built a product that people are using and you're going after growth, you would rarely get a chance to switch languages or frameworks. So, then, you're stuck with the language that you don't even like anymore for many years. I think you're also over-estimating the time required to learn a new language to be good enough for most startups. I understand that there are some areas where language mastery will be tremendous benefit. In that case, I agree that switching languages may not be such a good idea. But, that's a special case, IMHO.