That's true - but, as it is, if John Doe buys a gun and then I buy it from him, the government only knows about John Doe's purchase, unless I live in a state where citizens can't do that without a FFL as intermediary. (Of course, if I commit a crime with the gun, they come knocking on his door, at which point he says "oh no, I sold it to cheyinka!"... so I see your point.)

The carry permits thing is certainly true, though, and I guess it's just my distrust of the federal government that makes me not want that centralized, even though people licensed to sell firearms (for a living) or own machine guns or what-have-you are licensed through the federal government, and that works.