I found most of this book pretty dull, but that may be as much as, if not more than, a matter of my expectations than anything else. I bought it based on a positive comment in another article, thinking that it would be primarily, well at least largely, stories/histories of how individual composers made their living, with of course groupings and other aspects pointing out areas of commonality and difference. But what I confronted was chart after chart that left me far less enlightened that I had hoped to be. Moreover, much of it was based on length of space devoted to individual composers in a Schwann record catalogue of the mid 1990's, and I must wonder how realistic a basis this is. In short, while I do not quibble with individual conclusions, beyond the Schwann issue, some of which I did find illuminating and mildly interesting, I did not feel that I was really that much ahead after finishing it than I had been before I started reading it. In other words, a fair amount of the information, I found not very important or grabbing, but I repeat that this may be more a comment on me than on the author. Perhaps it is nothing more than, for me, it seemed to say that at least this take on on economics can be pretty boring.
As to advice for others, I would only say that if you want to know, and in some detail, how Chopin earned his way, or Vivaldi, or a host of other reasonably well known composers, this is not the place to go, let alone how the lesser lights listed did so. (Only one of the 600 plus persons cited I do not know, at least by name; while I am not more than a person who enjoys greatly listening to music and do a great deal of it, I claim no particular musical expertise.) But, as I have already indicated, it was not for me a lively read, certainly not what I had thought it would be.
Still, an impressive group of persons including Harvard's president (my school), think highly of it as a ground breaking and important study. I can only say it wasn't that for me.