My understanding of post-scarcity in the Star Trek world is that humans need not worry about their next meal. There will always be enough for the basic necessities. However, I do not think this extends to everything. My understanding of humans is that there will always be some of them who long to drive Ferraris, Lamborghinis, and live in huge mansions with servants to attend to them. A post-scarcity world can meet humans' basic needs but cannot change basic human nature, which is the desire to want more and more.
What if some humans want their own starship to play with? What if some humans want the most advanced holodeck at home for play? I doubt a post-scarcity economy can satisfy all of these "greedy" humans. Without money, how can these "greedy" humans be satisfied? Has the Star Trek economy declined into some kind of communist economy where no humans can aspire for luxury goods even if they are willing to work hard for it?