https://reddit.com/r/DaystromInstitute/ ... l_capital/
Now, I do think there are other reasons some people might choose to work, besides necessity- the sense of fulfillment that comes from actually doing something in the real world, a sense of duty, even the thrill that real world risk adds. But I think that this analysis largely hits the mark. Of course, the idea has been alluded to before in discussions, that higher rank may come with expanded privileges in the Federation, but this gives it an interesting twist. That social standing, likely as a result of social service, is the path to power and luxury in the Federation, even as basic needs are largely provided for.The currency of the future is social capital.
To preface: I've been watching Picard and immensely enjoying seeing my favourite Captain back on TV again...seeing Picard and Data in "proper" TNG uniforms made me feel all warm'n'fuzzy, like seeing dear friends again after a very long absence. But in watching PIC, I had a thought about the stark difference between today's Picard showing up at a planet and getting the cold shoulder, versus TNG's Captain showing up and getting the red carpet treatment:
In the 24th century, your personal wealth and power is measured by the amount of social clout you wield and the breadth of your reputation.
I think a generally-accepted premise of the Trek universe is that the Federation exists in a post-scarcity time (and for the moment, let's keep this confined to 'central Federation worlds', and leave out the borderlands and edge cases like DS9 and its gold-pressed latinum, etc.) On Earth and other 'core' worlds, there is no poverty, there is no hunger, there is no want - every Federation citizen is looked-after and provided for.
But people still work. Picard has his vineyard, Joseph Sisko has his restaurant, Jake Sisko is working to become a reporter, Keiko O'Brien is a botanist, and of course all our main cast members are active, working members of Starfleet. If these people aren't getting paycheques, then why are they going to work? If you could get all of your needs met (by way of the Federation's utopian, post-scarcity society) and just go full hedonistic in a holodeck 24/7, then why wouldn't you? What is driving all of these people to go to work instead of being on holo-vacation every day for the rest of their lives?
I propose that the motivations that drive our favourite 24th century people aren't quite so different from those that drive 21st century people today; but instead of money being the thing in limited supply, it's social clout. Current-day people still continue to work even after they've made enough money to meet their basic needs, because in today's world having more money means you have more power (in the "to be able to" sense). Being money-richer than you need to be for survival provides you with the power to take time off work, or engage in leisure activities, or to tailor your lifestyle to better fit your specific preferences, or whatever you choose to spend that power on.
Turning back to the 24th century...if we assume for the moment that in the future, your reputation dictates your wealth, then our TNG-era Picard is filthy rich. He's known far and wide throughout the Federation for his career accomplishments (which I won't retread here), he's in command of Starfleet's flagship, and his voice carries an immense amount of weight with those in power. When TNG-era Picard goes into orbit around your planet, you put on your Sunday best and dust off the good china, because you've got a VIP on your doorstep and he's rich and powerful.
In contrast, look at the reception that PIC-era Picard gets when he shows up at Vashti aboard the La Sirena - they essentially screen his phone call and send him to voicemail. PIC-era Picard is dirt poor; he doesn't command any ship, let alone the flagship; he's had the door of Starfleet slammed in his face, he doesn't have the ear(s) of those in high-ranking positions...he's lost all his social clout. He's lost all his wealth and power.
I think this idea of "reputation as wealth" also explains why people still do real work in the real world, and not just play-work in the holodeck. If Trek people's only motivation for working was because they absolutely loved to do what they do professionally, then why not just do it in the holodeck to get all the pleasure from that activity with none of the unpleasant or dangerous parts? Joseph Sisko could cook with holographic food and not have dishes to clean up afterwards; Jake could write about anything his holodeck-imagination could dream up and never be in any actual danger from a war front; Keiko could tend to holo-plants that would always flower and bloom perfectly and never get her hands dirty, and none of our starship crews would ever be in harm's way. But holodeck activities would never generate real-world results that require skill and ability to achieve...and would therefore not burnish your reputation and increase your wealth.
In the Federation's post-scarcity economy, all of one's physical needs can be taken care of without difficulty. Replicators and Trek's apparently-infinite energy sources make short work of any tangible goods being in demand. But there is only so much reputation to go around. No matter how many widgets or gadgets people need or want to live their best lives in the Federation, only one person can be the top person in their field. Only a small group of people can be the best / most qualified / most knowledgeable / the recognized authorities in their area of expertise, whatever that area is. This is where scarcity still drives the economic activities of the future; this is why people still go to work: to be rich and powerful by way of their personal or professional reputation.
TL;DR: the currency that drives the Federation's economy isn't something tangible and replicator-able, like cash...it's reputation and clout.
Edit: It also makes me wonder if the Federation's culture is really that different from the Klingons'. The Klingons gain prestige as warriors by following the Klingon honour code- while Federation citizens gain privilege by acting "honourably" within the Federation's social code (ie engaging in some form of accepted public service).