I very much appreciate this brief article by trumpet player Jeff Purtle: Why Do Musicians Charge? Mr. Purtle makes the point that it costs a lot of money to be a musician. This is painfully true for woodwind doublers, who need not only a large number of high-quality instruments, but also reeds, maintenance and repairs, insurance, stands, cases, and more for each instrument, not to mention the cost of lessons or even college or conservatory study.
I think the overhead costs of being an instrumentalist are a really important and valid point. But I do think are some more reasons why musicians should expect to be compensated fairly for what they do: