I hear you and I'm sympathetic. I do tip reasonably, and how much depends on where I'm diving, with what type of operator, level of service, etc. etc. but here's what I REALLY think about it:
I find tipping to be in the same league as a service or convenience charge on concert tickets; the ticket is $50, but the "service charges" add up to $10 per ticket (for example). I resent being presented with a certain price, then having to pay additionally for "service". I feel any provider of a product or service should charge what it costs plus a profit, put that price out there and that's what the consumer decides to pay. So, whether you're a concert promoter or a dive operator, charge one price and that's it! That includes your 60-hr weeks, your insurance, labor and harbor expenses, etc.
If you fail to do this, you are accepting the risk
that you may not get tipped, either because of the ignorance of your customers, their country of origin, or their plain outright cheap-itude. You may use the excuse that if you stated your price accurately, with everything included, no one would buy, or you would appear to be more expensive than your competitors. To address these two issues, I would offer the following.
"The customer may not buy": The customer has to make a decision, and you can market the dive trip as "all inclusive--no additional charges or tipping required". I'm sure there are a lot of folks like me who would gravitate to that sort of marketing.
"We would appear more expensive, less competitive": Again, it's about educating your customer, marketing, and understanding that those who don't tip, don't understand about tipping, will go to the other operator. Either operator has to decide what profit margin they are willing/able to operate with, understanding that to depend on tipping, especially in a tough economy or with an international customer base, is a big risk.
Overseas on a liveaboard, many operators just state that they EXPECT 10% of the price as a crew tip--they depend on the tip to pay their crews (including the background folks like cooks, engineer, etc.). I think this is unconscionable, really, and the crews end up hating those whose culture it is to not tip. Why should I tip the ship's engineer, or cook? Or the customer may have had good service from one crew member but poor service from another. It's crazy.
This is the INDUSTRY's fault, IMHO, and they should just charge what it costs plus their acceptable profit margin. If I choose to tip the guy who recovered my camera when it came off my wrist and floated up to the surface (which I did, and generously), then yes, tipping is appropriate. But to expect me to tip to pay everyone's salary, that's crazy. Just charge what you need to charge, and if you don't, you run the risk of not getting that tip.