Anything that’s generally-available retail doesn’t need a license. Because to insist upon requiring government permission to export something anyone can buy at Walmart is just being stupid, right? So, in the cases I listed above (industrial quantities of uranium, radiation-hardened chips), a license is still needed. Fast computers, which a few years back would need that super-difficult license, now need none at all, thanks to the electronics aisle at Best Buy. PGP and similar encryption are just fine to export today because that level of encryption is everywhere.
The legal argument against 3D gun designs being posted on the Internet has nothing at all to do with domestic U.S. availability; it was about export. Since it is now obvious that such designs, and the ability to 3D print, are going to become commonplace, there’s no reason to restrict export ability — just as with the more general retail availability argument.
It’s true that this could change the availability of guns and law enforcement’s ability to trace them and so on. We may or may not like this new world being ushered in. But there’s no point in trying to restrict it, because doing so just won’t work. So, we’ll not.