There is definitely some evidence for this hypothesis. If you read about the restaurant industry you'll see a lot of comments from restauranteurs that seem to indicate that they think the salary ratios between FOH and BOH staff are off.

We've had a couple of restaurants in NYC go tip free, instead building the cost of service into the base cost of menu items. Unfortunately it appears that this can be a challenge because consumers aren't used to the higher cost menu items. Even though a $30 entre with no tip is roughly the same cost as a $25 entre where a tip is expected apparently consumer behavior changed significantly. Quite a few places have abandoned their gratuity free plans after a couple of months of testing.

There might be a bit of a prisoners dilemma problem here. If every restaurant eliminated tipping consumers would soon get used to new prices, but when only a few do they stick out as feeling more expensive (even if they really aren't).

We might currently live in a stable but non-optimal equilibria.