Well, the Federation could still be post-scarcity...it's just that everyone who's left out of that society who isn't.
When you stop and think about it, all the Space Pirates that we know of are aliens. And they seem to be focused on targeting human colonies on other worlds.
Are the Space Pirates actually..."natives" of different worlds who have been displaced by the colonizing humans? We know that the Space Pirates DO want to steal other worlds, and claim them as their own home-worlds. Which could mean they don't have a home-world of their own, anymore, for some reason.
And, again, apparently Samus's Chozo tech and Federation technology are compatible. Since, the Federation can control Samus's suit in Other M. And Federation Missile upgrades and other power-ups work on Samus's tech. So...is it possible that the Federation's technology...IS Chozo technology? That they either stole or discovered on their own, in some ruins?
Is the Galactic Federation actually the baddies? Promoting Human colonizes at the expense of all other life in the universe? Allowing them to have a post-scarcity society by conquering other worlds for their resources? Using their influence to force any other alien species to either join with their government, or be labeled as "Space Pirates" to be hunted down by their privatized security forces, the Bounty Hunters?
Is Metroid actually...the "Mirror Universe"? I mean, the Terran Empire was still a post-scarcity society, too, wasn't it? It just went a VERY different direction than the main Star Trek Federation.
Metroid WAS originally inspired by by the Aliens franchise. And Weyland-Yutani was pretty Orwellian. So...
...I mean, probably not. I probably went a little too far there. I don't think Nintendo would be okay with something like that. Even FAR in the background of the story. And it does kind of go against the whole "Generosity Hunter" angle, I'll admit.
But, then again, Samus is basically a "country girl" raised by alien birds who might not fully understand who she's working for.
I don't know. I find it a interesting idea at least. I'm REALLY not sure it works, though.
In a post-scarcity society with no money, there would be no piracy. It would be hard to define what piracy even is. The Federation must still have money and scarcity.
I imagine "piracy" would be all about control, in that scenario. Who gets to be the one who tells everyone else "no"? I mean, again, we see the Federation being able to control Samus's suit. Who gets to be the one in control of that system?
And it might be a fair point that "ordinary people" have a limit on what they're allowed to replicate. Just being able to make their own weapons alone without government approval might be enough to call them "pirates". They don't have the correct license to allow them to do that. They are breaking their laws.
Plus, again, "jail breaking" the "copy protection" on the weapons they steal would make them "pirates". They're basically breaking the DRM on the Federation tech.
Plus...the whole "stealing planets" thing. That's probably a big one.