Straydog,

I think the point people are making about Guides costs are that they aren't getting rich. A good guide can make a good living though. And you are right that they can certainly do something else. A good guide loves his/her job.(Or at least most of the time)
One note that I mentioned earlier and some other people have also mentioned is a guide making an extra effort. For example I have a good friend who guides up in Hells Canyon in a jetboat. On slow days I have seen him burn over twice the normal fuel running around working his butt off hitting every little spot he knows to get a few fish. At the same time I have seen some of his competitors working the same tired old spot all day and saving fuel and not catching fish. Now my friend doesn't expect a tip because of this, he works hard at it because he wants to get his clients into fish. However, to me that extra effort sets him apart and in my mind as a client he has earned a tip from me. People have used the example of not tipping the plumber etc, but that is not always true. I go to college and do electrial work on the side. When I do work for these people I make a point of doing very nice work and as fast as I can. The last three jobs I have did, when I got paid my customer had added an extra $50 or so because of the "great job" I had did. Do I expect it? No, but I am always appreciative. And as someone mentioned above in most businesses extra effort results in bonuses and promotions.
One last note, people always talk about guides fishing all the time. In reality, most guides help other people catch fish all the time. Spend all day running a tiller while watching people miss strikes, foul up gear, and treat high dollar equipment like garbage. Yes it's all part of the job, but seeing it gave me an appreciation of the effort it takes sometimes.
Sorry such a long post.
Tom