While not quite from scratch, I have built guns. I might add that it is a very interesting and educational experience for anyone interested. Also, know that so long as you aren't a felon and the gun you build complies with federal and state laws, it is completely legal to do so.

You've assembled guns, probably, from parts you purchased. Like Legos. I doubt very much that too many people are hammer-forging 7075 receivers in their garages...

Drawing back to the original point, who is building a drone, or anything. There is only one guy I know of (primitive technology on you tube), and the most advanced thing hes made is a hatchet and charcoal.

This is like saying you didn't make homemade bread if you didn't grow the wheat out back. It is a pointless statement countering an assertion no one asserted because the rest of us know that home made bread means from store bought ingredients unless specified otherwise.

Likewise, I doubt that too many people are etching flight controller PCBs and building brushless motors from scratch in their garages.

You’d be surprised then - first of all, no “hammer-forging” is required, nor is 7075 whatever.

Take this for example (warning, language!) https://www.northeastshooters.com/xen/threads/diy-shovel-ak-...

This is actually my point. It didn't say "no one" is doing it. Even though his means are very crude, he still needs a furnace, a welder, and a lot of other tooling (receiver jig, etc.) to get to the point where he can use a bucket of pre-fab parts (most notably the barrel).

That guy is building a receiver, then assembling. Most people who are into it are just assembling.

From scratch, as in from bar stock and other raw metals? Yes, very easily, in fact. It's technology that is well over 200 years old. Machine guns are 100+ years old.

Making primers and smokeless powder might be tricky, but the mechanical stuff is easy peasy.