Also, upgrading equipment, for example, is a small cost spread out over time. A new business has to cover it all up front which boosts starting costs and makes it harder to raise capital.
A lot of people find the hassle to just not be worth it.
In my view: sometimes this is a good thing - we don't need a glut of businesses by people who aren't quite business savvy. If someone sees the measures necessary to start a business to be not worth it then there are many things about running a business that might prove to be too demanding, too.