Welcome to the coin market. The only way it really works out is if you're a coin shop and you're having a hundred or more coins graded at a shot; price drops dramatically per coin, and the maybe 10% that will be of the higher grade justifies the cost.
An individual getting a single coin graded? If you think about it, overall labor in handling that coin from receiving it, to keeping it identified as to the owner, to making sure it gets back to the owner (and not mixed with another coin) - that $30-$40 is likely losing money for the grading company.
Agreed. For a single coin, unless it's something pretty extraordinary, it doesn't seem to make sense. What might make more sense, for someone like myself who has just been an occasional collector, (other than proofs, the vast majority of what I have coin-wise was purchased for face value when I was much younger, and worked in a grocery store as a cashier), it might make sense to take the ones that I think might be worthwhile to a local guy, and have him give an opinion on what he thinks would be worth having a professional grade for.