Post-scarcity in some ways, perhaps. In many other ways, they're not.
Star Trek still had merchants who sold various wares. That would not be profitable if nothing was scarce.
They still had planets that lacked necessary medicine, requiring The Enterprise or some other ship to go on mercy missions to deliver the meds.
The Star Trek universe had pleasure planets which had highly desirable things that other planets did not.
There was clearly a shortage of starships and crew, as The Enterprise explored alone and not in a fleet, and couldn't just create a hundred others to help it when it was attacked by some alien enemy.
The Enterprise couldn't even use their on-ship replicators to make themselves some dilithium crystals (fuel) when they ran low.
