There is a huge difference between expecting a tip and being insulted when someone tips you. Which is it? Do you actually know any tour company owners?
I would say it is more of a case of no expectation of a tip is usual, but grateful when it happens. Most guides work for themselves as well as for other tour companies and I don't know a single one who "expects" a tip, nor who asks for one, but they all are grateful for them, and use any tips received to help pay the rent. We are talking guides in 4 different European countries, cause I have asked them. Not one even mentions tips nor asks for them, but all are happy, not insulted. None of them are rich.
Jan, you have twice used the word flunky when describing guides. Why? That is a pretty disrespectful label to use when speaking about people who guide for a living and who work for someone else. People who have spent considerable time and effort to learn a subject, perhaps years at a university, travel on their own for research, working in all sorts of weather, who are passionate about their subject as well as putting up with 1000's of ignorant questions with a smile. Interested in how you know what they receive for doing a tour. Do you think they are not well paid? That the tour owners just toss them a pittance for their sharing their knowledge with groups of paying guests?