A reader from the Eastern Seaboard emailed me this question a month ago. I'll have a much more detailed answer next week, but my initial response is "Absolutely not.'' I realize that I'm only going on my own very limited experience, which took place quite a while ago, but just about everyone I met out on the trail was not well-off at all (and some were strictly subsistence.) As for me, I left a very low-paying job to do the trek.
Also -- there are opportunities to save money by preparing your own foods and making at least some of your own gear. More on this later.
(by the way, thanks for sending in all these questions over the past few weeks. While I am probably the last person on earth that you should ask for backpacking or survival advice, I can at least refer you to folks who know the answers.)