Oh, we have those machines in hand loading now. Tool and die guys do that for not more than a few hundred. It's just that the risk-reward ratio isn't there, for the most part. Cases are pretty cheap and the penalty for screwing up making your own is a bit high. Right now.
In the Future, who knows. Auto-CAD stuff lets you take existing designs and make your own stuff, but I don't know if it's any better in Imaginary Future than now in terms of replacing existing cases.
Auto-CAD is also limited in it's versatility, which is why Malorian Arms and Militech still innovate, design and sell.
Edit: although as I think about it, if a Tech in my games wants to do ANY of this stuff, we've talked about, I'd tell him to go ahead and set it up for me. Most of what I've said would apply to my decision via non-Techs. In 2020, there are so many technically trained and apt persons, they'd really change how backroom homebrew works, I think.
You don't have to turn around, Redge.