Sure, and once you have those in place you have a startup that eats money and doesn't necessarily make any money. The vast majority of software startups end up building something that nobody wants anyway, because if there's something that lots of people want, somebody has already built it.

Whereas if you open a restaurant, you can make solid projections where "If we fill every table, we make $Y. If we're 1/3 full, we make $X. We're unlikely to be less than 1/3 full", and these are typically completely reasonable because you can see how other similar restaurants have done. For a restaurant, having a similar restaurant be successful is a very positive indicator. For a software company, having a similar software company be successful is an indicator that the market niche is already filled.