Even worse is when you evaluate hiring. It isn't unusual for a high-turnover entry-level type employer to have 15% or less of candidates who agree to fill a position still employed with the company 6 months later.
The pure drag of having to deal with this, especially when it comes to all of the paperwork required, by law, to be completed with every single new hire makes this alone a huge expense.
The vast majority of those employees left of their own will, not because they were fired. Usually when the leave, there is no notice. They just don't show up leaving management short handed and wondering whether the employee will show up the next day. Consequently, the policy can be to over-staff so that whenever some percentage isn't showing up the employer can still meet production needs.
The employer cannot simply increase prices and pay people better. For the most part, employers already have prices at the highest their customers are willing to pay. Setting prices higher will result in loss of customers, less profit, then layoffs or business closure.
Employees at this level are astoundingly uninterested in performing well, or, in other words, there is a reason they are working entry-level positions. This makes management yet more difficult because managers may have to become near micro-managers of cat herds trying to get the company to produce whatever it is supposed to produce.