This is just my personal opinion, but I think it's a greed issue with a touch of laziness and an unwillingness to face even the mildest inconvenience. I think the pandemic showed us that our mammoth corporations aren't going to save the day, unless they can make a big profit from it. Food deserts would be the "new market" to conquer if there was money in it. And there aren't enough people who are willing to make sacrifices to make a change. We demand cheap food that's easy to get and in enormous amounts. It all factors into what drives the supply chain. I'm guilty of it too.