His economic theory is 101 level. It looks at the economy like everything else is equal, when in reality nothing is.

There are fields where his idea is closer to truth, fast food and grocery stores have low margins for example, but even then record prices occur at variable times. Grocery stores are making more currently due to inflation for example, but it's record profit that aren't as meaningful as it sounds.

He also forgot the capital part of capitalism, you can't just pluck a new company down and start selling. It takes money (capital) to build a store, get goods, get employees. This means competition is always based on how likely a return is for capital spent.