No, it's because it's not profitable to do so, and the big players will kill your business. This is also tangentially mentioned in the article... You think you can compete with PotatoCo, which makes billions of dollars, has massive scale, owns several Senators, and which every last potato farm in America is already using? And you want to blame the food regulations that keep people from getting sick and dying?
But sure, just go "start a frozen potato company". Why didn't anyone else think of that until Hacker News?
The article isn't about consumer apps, though, it's about websites that all four companies in an industry use for "optimal pricing", which just launders collusion through a Python backend. I would considering giving the piece a reread.