From what I can tell, market theory assumes it's easy to enter a market or that people with money to spend somehow want to use it to compete knowing that they'r

From what I can tell, market theory assumes it's easy to enter a market or that people with money to spend somehow want to use it to compete knowing that they're doomed to drive the industry back to "normal profit." Nobody investing money actually wants to throw money at something that will obviously drive a return to normal profit by competing, and do so within a few years after significant capital expense. They want to invest in something that will drive margin growth. Instead, the only reason people do it is to get a buyout offer from established businesses in the same market. Unless you're Mark Cuban. Though the above is only true to a point - obviously if the margins get high enough or product deviates sufficiently existing businesses with related interests will step in: witness Costco's chicken business. So maybe the question is less why isn't there more competition and more so why haven't restaurants vertically integrated their potato supply? The main theory I'd have is that price increases haven't negatively impacted their margins or revenues sufficiently yet.