[ErrantX]

> if you were simply to collect that data yourself, sell it on the open market, and spend a portion of the proceeds on the tax prep service, you would end up with profit, and the tax prep service would still exist.

Economies of scale; the market for that data would not exist if individuals collected it themselves to sell. Hence would break down.

Phrased another way; this data about 1 person is relatively valueless.

(I like the rest of your example BTW; just disagree with your conclusion)