I do tend to agree with you on that issue, blowero. After all, restaurant prices go up, so, as you say, this increase should, by itself, result in a commensurate increase in the income of wait staff. Increasing the prices, and increasing the percentage over time, seems a little ovewr the top. Will we some day arrive at a situation where the tip is expected to be 80% of the bill?
When i worked for tips in a casual lunch place in Vancouver, Canada about 12 years ago, we tended to consider 10% the absolute minimum. If we got this much, we weren’t exactly thrilled, but it also was no cause for major whining. In general, 12% seemed to be about average, 15% was good, and anything over that was a real bonus.
Of course, the place where i was working tended to cater to a lot of tourists, who are notoriously cheap-ass with their tipping. This applied not only to Brits and Aussies and Kiwis and Germans (who at least had some sort of excuse, in that tipping is not part of their normal experience), but also to American tourists, some of whom seem to believe that tipping is no longer required once they cross the border. And, of course, tourists know they will likely never return to eat at that place again, so their incentive to keep the staff happy is pretty low. The best gigs at that restaurant were the pre-booked tours, where tips were already factored in to the cost and were distributed to the staff at the ned of the shift.
When i moved down the road a bit to a higher-class place that mainly served locals, tips tended to be quite a bit better. 12% became the minimum, and 15% was more like the norm.