Entry level positions in any field typically don't pay an exorbitant salary, but you are correct in your assumption that in most cases back of house staff makes less than front of house. I made about 2/3 of what I make in the front of house when I was a chef. Dishwashers, for example, make significantly less than a line cook, who makes significantly less than a chef, etc. And that's pretty much how you move up thru back of house thru experience.

In the US there is a tax structure and a minimum in regards to what a server can get paid though. The real problem is that minimum wage has not been adjusted enough for inflation, and is therefore not a living wage. That said, if a server makes $2.65/hr, and the state minimum wage is $9/hr, the server must receive at least $6.35/hr worked in taxable tips. If the server doesn't claim enough to reach their state's minimum wage, the business must pay the server the difference.

We use a 20% pre-tax gratuity to sort of standardize the amount that you make but honestly in fine dining it's typically better to roll the dice (most americans tip 20%+ AFTER tax in fine dining). That decision is the server's choice though. I do make it mandatory for my servers to automatically put gratuity on parties of 5 or more (for congruency sake), but allow them to make the decision on small parties.

It's actually all a bit more consistent and regular than anyone could imagine. Sure, slow months hurt and good months rule, but at the end of the year, I can almost positively bank on $XX,XXX.