There are absolutely millions in poverty in developed countries like the US who do not have any ability to buy fresh food.
Being able to eat healthily is a privilege in 2025, which is fucking disgusting, but absolutely true.
There are towns in America where the only place for a hundred miles they can buy food is a dollar store. These shops don't typically stock anything fresh or particularly healthy.
The people there will be too poor to live anywhere else and might be working multiple jobs (as is typical in American poverty) so will not have time/energy to attempt to grow anything themselves
We are lucky that we can eat healthily, but don't let yourself think that's a choice everyone gets