When I was last in the US I noticed that restaurants generally seemed to charge similar amounts to my expensive city (Sydney) but that was before the tip. So is

When I was last in the US I noticed that restaurants generally seemed to charge similar amounts to my expensive city (Sydney) but that was before the tip. So is it a lot more profitable to run a restaurant in the US because you essentially offload the labour cost from the meal to the tip but can keep the meal a similar price? Also if its something that is generally always expected to be 20% then why not charge extra and pay your staff normally rather than having this extra layer to potentially mislead diners?