I think the point is that if all the staff do is pack up take out orders, they legally cannot make them do it for $2.13/hour. The employer legally has to pay tipped employees minimum wage if tips do not cause them to reach minimum wage. More time on take out orders is less time earning tips.
More broadly, most wait staff aren't going stick around even if they're being paid minimum wage and getting no tips. They'll go elsewhere where they can earn better — presumably somewhere they can consistently earn tips.
Wrong. https://www.dol.gov/agencies/whd/state/minimum-wage/tipped "Basic Combined Cash & Tip Minimum Wage Rate" means that if tips do not meet the federal minimum wage, the employer must make up the difference.