It's really not a binary situation where you'd ever see $2 wages with no tips though. If less people tip then the effective real minimum wage will gradually increase to compensate - either because laws are updated or because the restaurant has to compete with other better paying job opportunities. Sure some waiters may get upset when someone doesn't tip, but that is just that - them getting upset - and not the client being an asshole.
This will hurt people in the moment, people who sometimes are few dollars away from not making rent or buying enough food.
And as other commenter correctly pointed out, by the federal law of hour wage plus tips is below federal minimum wage, the restaurant must pay extra to reach the minimum wage. So if we assume that restaurants actually follow this law, wait staff will be kept at poverty wage 7.25/hr.
