Wal Mart stores aren’t understaffed due the lack of willing labor even at Wal Mart wages. It’s because mangement rations the wage budgets that supervisors have to put workers on the schedule. It’s a standard way to manage a big box retailer or supermarket, but it’s really easy to screw up. Wal Mart is prone to it because they long ago gave up on marketing themselves as a nice place to shop. Bad customer experience is par for the course.
You are right. They try to squeeze every penny too tight and it is driving off shoppers. Standing in line for 30 minutes, out of standard items, dirty stores, etc..