In theory it should be possible to manufacture IC's at home, similar to 3D printing. And a (very!) few people have even done so. A whole lot of progress in IC

In theory it should be possible to manufacture IC's at home, similar to 3D printing. And a (very!) few people have even done so. A whole lot of progress in IC manufacturing is making things smaller. No reason one couldn't include the fabrication machinery itself in that quest. Another approach is to fabricate IC's in a blank state, and have end users 'burn' its function. FPGAs are a thing, iirc even some fuse-programmed ones exist. Some gate arrays consist(ed? not sure if made anymore) of bulk, prefabricated logic, with a layer of customer-specified routing on top. Something like that could lend itself well to 'diy-at-home'. All these would sidestep much of the "trust 3rd party" problem. So yeah it's possible. Technology (or more precisely: equipment on the market) just isn't quite there yet.