If resources are completely unlimited, the argument goes, it doesn't matter if they are used inefficiently. But .... there is in fact economic scarcity in the Star Trek universe, because not everything can be replicated (e.g. - power sources for starships and replicators themselves). Moreover, the Federation and other nations in that universe wage war over the control of planets and other assets, which implies that they can't be replicated either. It's also worth noting that replicators seem to be a government monopoly in the Federation, at least on Earth; I don't think we ever see a private replicator owned by a human Federation citizen. That has some troubling implications of its own.There are a lot of assumptions here. And absence of evidence is not evidence of absence. Look, this is "Star Trek", it concerns itself with an outer-space navy. You're not going to see lots of details about civilian life in the 23rd century.
As to replicators: if a device went on the market tomorrow that could turn a box of gravel into a laptop computer or a gold watch or a three-course dinner, and you didn't think it would completely upend our entire economic system, I'd say hold out your arms so that I can get the straightjacket on you, there's a good fellow.
Somin goes on to complain that there is no money in the Star Trek universe (and I agree that this is unrealistic even in a replicator-based economy, since money is a yardstick for measuring the value of human labor, not just consumer goods). But then comes an interesting generalization:
[W]e never see any large privately owned enterprises in any of the Star Trek series set after the founding of the Federation. We never hear such of such enterprises being mentioned, or see their brand names on any goods.
Again, absence of evidence and all that. But more importantly, expecting that the world two hundred years from now will look the same as it does now -- well, it doesn't make sense. We don't really know anything about what the future is going to be like except that it's going to be different -- radically different -- than it is now.