[justin]

Even startups not aiming to be the next FAANG company have trouble estimating revenue, product development time, etc. It's just extremely hard to know all the unknowns when you are starting a new business, especially since it is likely that you are only an expert in one of the required fields (eng, product, marketing, sales) to bring your product to market and will have to learn everything else on the fly. Most business plans for startups are useless.