My first thought: It's could be very difficult to build a product to a stage where product-market fit can be assessed without external financial assistance. I think most products can be brought to this point in a year or two with a team of 2 or 3 people, but that's a pretty sizable chunk of living expenses and possibly salary that needs to get paid.

If the only people who can start companies are the ones that have at least a few hundred thousand dollars in the bank, that really limits the field. I think VC probably plays a beneficial role here, opening it up to people who otherwise would have no freedom to spend a year or two pursuing an idea that may or may not convert into a profitable business.