Most wait staff in the US make about $2.13 an hour, and don't get any benefits, no healthcare, nada, nothing. They depend on tips to make a living.
My mate might make $80 to $140 a night in tips, but they are taxed, so the pay-check is always zero. So he might clear $2,200 a month on average, but generally owes on taxes, and then health insurance is not cheap.
If restaurants had to pay $7.25 (or more) in the US, you would instead pay higher menu prices, plain and simple, and the wait staff would have less incentive to provide excellent service. I waited tables for many years, and, believe me, non-tipping customers are noted, and get slower service, and I have seen people even spit in their food. Which is rude, but it's a stressful job, and if it is the only thing you can find in an economy like the one we have now, it can really be frustrating not to be tipped. You might 'demand' a better wage, but you are more likely to be shown the door by the owners.
Not to mention, you are taxed on your implied tips, on your total sales. Say you give a table a checkfor $50. You will be taxed as if they left you 10%, or $5, even if they leave you nothing. So by not tipping, you are actually taking money from them.
If you can afford to eat out, you should also be able to afford to tip.
Oh, and I heard from this voice in the heavens that there's a special place in Hell reserved for non-tippers, where it is twice as hot!
Kidding, on that last one.