[evanwise]

The only possible reason for barriers to entry is regulation? There are many industries where startup costs are high for reasons intrinsic to the business and margins are relatively low so you are unlikely to get investment from outside sources. Grocery stores for example. You are trying to apply a toy model from econ 101 to explain the behavior of complex real world markets, and when the model doesn't fit you invent bogeymen to blame. This is more like religious fundamentalism than any kind of science.

[randomdata]

Grocery stores are already operating at rock bottom – in most markets, at least.

It is not that difficult to try opening your own grocery store. In fact, many restaurants did exactly that during COVID-19 shutdowns. Realistically, succeeding is going to be nigh impossible, though, as there is not much you can compete on. You are not going to be able to sell the product for less.

It is not meaningfully bound by a regulatory barrier, but it is limited by there being no further room for competitiveness, as also spoken to in the previous comment.

[lotsofpulp]

I find it very funny that a forum of people who ostensibly work in the highest profit margin businesses in the world, enjoying the highest industry wide compensation to quality of life at work ratios, claim that the lowest profit margin businesses in the world with some of the lowest compensation to quality of ratio work has enough pricing power to allow them to reap undue windfalls of profit.