From what I understand, the reason there are no more Uzis being imported into the USA is because of the AWB in 1993. The same goes for AKs, etc.
I believe it was Bush's ban on non-sporting semi-autos that started things, not the Clinton ban, although I think Uzi tried to get around it. Otherwise, with the Federal ban expired in 2004, they'd be back. There's also the issue of open bolt/closed bolt, but I imagine semi-auto Uzis these days would use a closed bolt.
AKs are being imported, see Arsenal, Zastava, Cugir, and others...they're just jumping through hoops with 922r, opening single stack magwells, etc.
But why are there no variants being produced in the US like there are with AKs? Why, if we have a great relationship with Israel, has this ban not been lifted?
Good question, although it's clear Democrats don't want any more firearms imported and most Republicans, the president included, would rather not upset US manufacturers than allow imports. Trump hasn't let Saigas come flowing in, or Type 56 rifles, etc. There appears to be little political will to do favors for gun owners.
Why aren't there any US companies which specialize in reproductions, like with the MP5? Is this due to copyright/patents?
It's not cheap to start producing guns. Materials, machining, prototypes, trials, etc. How many people would want to spend $1000+ on an Uzi that's going to be inferior to practically every other PCC out there? You either get a pistol version and deal with a brace or a $200 tax stamp, or you get the ugly looking 16'' carbine versions that offer nothing other than nostalgia and then decide whether you want to SBR it.
I just don't think there's a market out there for what a semi-auto Uzi brings to the table. The MP5 clones exist, but the MP5 design is still viable, and the clones are still going for roughly $2000+. Who's lining up to buy a $2000 semi-auto Uzi? Not enough people to justify the start-up costs, I'd wager. There's plenty of PCCs out there that are much more modular and accurate and cost fractions of what an Uzi would run you. The Uzi itself is kind of niche, and there's enough originals out there to satisfy the demand. I know exponentially more HK fanboys than I know IMI/Uzi fanboys (I actually am not sure I know of any real Uzi diehard fans, but I'm sure they exist).
This, of course, is different than the 22lr Uzi GSG was making. I think it's like $300. That, theoretically, could be fun to cut/crown and SBR as a plinker.