Actually, I've never once heard anyone say we should tip them because of their base wages. I have no idea what they're paid nor how efficiently or competitively that labor market functions. As an outsider, it seems like it's a gig everybody wants at one point in their life or another, leading me to believe that the overall pay including tips is relatively good. I'm in the minority amongst my friends in that I never worked as a waiter or, once old enough to do so, a bartender.

I suspect that tipping entirely predates the concept of governments manipulating labor markets via a minimum wage but don't really know that for certain.