I’m just guessing, but it likely requires scale in order to become profitable. Building up the necessary network, infrastructure and logistics, while getting up to speed on all the regulatory requirements, would require a lot of difficult work. VCs also wouldn’t fund something that merely becomes profitable, without a chance of making stupid amounts of money. The number of “founders” who would want to make this their carrier is constrained by that limited prospect as well, in addition to “selling potatoes” not being very sexy. And the price-fixing cartel would try to thwart you at every step.