$100 per user a year? It would not need to be any more than $6. Read on:
The way I see it, $6 a year from the 180 million people on the internet in the us alone would net the industry (hopefully the artists) $1,080,000,000. Fifty cents a month for unlimited downloads and knowledge (through an aforementioned third party like soundscan) that the artists would be paid? That's fine with me. I don't know why you'd think it would ever be $100. A $6 annual surcharge would be invisible to most consumers. Most people spend more than that on a happy meal.
It's clear that 60 million people do not want the old distribution system anymore, they don't want to pay $.99 a song or $10 an album for something that has zero distribution costs, especially if apple gets $.35 and the RIAA gets $.65 of which they dole out maybe $.08 to the artist, who must pay it back to the label for production costs. Per-song per-album just won't work anymore. Neither will any form of drm. No matter which option gets chosen, p2p will always exist and millions will use it. We're looking at something akin to the war on drugs here, and things are only getting started.
That's my two bits.