Most people are born and raised in the same city or area their whole lives. The adult illiteracy rate is 20% and less than 40% get any kind of 4 year degree. Options are limited. People will cling to hope and the life (and community!) they know, until they're broke and lost their job... and at that point, they straight up can't move to Fresno and start that Walmart job. Walmart wouldn't hire them without a local place to live, and cheap Fresno landlords wouldn't rent to someone without a local job. Neither Walmart nor the landlord has an incentive to change, they're doing just fine exploiting the local Fresno populace.
Low-skill/low-pay life situations are a completely different reality than what well-off knowledge workers know.