I suspect a tablet could probably be assembled in the US now, probably the case mouldings done there as well, might even be economic. But all of the electronics would almost certainly be Chinese or Korean.
I'm sure there's a lot of electronics made in the US, but AFAICT it's nearly all high-value military and defense stuff. Not low-value consumer electronics, like Android tablets and phones, laptops, TVs, DVD players, etc.
I think companies like Apple, Dell and HP design and develop their products in the US, but then all manufacturing is done here in China. Sometimes even R&D, is done overseas as well in places like India and China. But on the other hand, if it's just some guy in a Brooklyn apartment wants to do his own tablet, He just goes straight to a Shenzhen OEM, who've already done all the R&D for making Android tablets, and tell them what options and branding he wants.
The People's Guide
to Android in the People's Republic.
Honorary Grand Poobah Shenzhen University English Corner.
There are nine million bicycles in Beijing.
There are nine million Androids in Shenzhen.