This keeps coming up. The major labels are falling over each other to release P.R. claiming that the RIAA's lawsuits are working -- that file swapping is down. Trouble is, file swapping's not down -- it's just moving to networks that the lawyers haven't caught up with yet.
As always, it comes back to this. It will always be EXTREMELY difficult to make a living just from selling your CD's. They're a strong tool for you to have as you grow your audience and book more gigs, but you're not going to get rich from them. Even less so if you get signed by a major label. If you're making music that's attractive enough for folks to swap, revel in it. Find ways for those listeners to contribute to your cause. They will.