Trade might also be family tradition going back to the boomers (like Travis' family on the Horizon).
Picard's winery was traditional.
Sisko's cooking skills were traditional.
As for why people don't stay on Earth's utopia, or don't just move back there? Maybe they just don't want to. Maybe the want to feel like they earned what they get rather than have it handed to them. I run into people like that that insist they work for what they get even if they can get it free. A lot of the people that lived though the Great Depression seemed like that. Defined by their job regardless of how much money they had. They could have had enough to do whatever they like if they retired early, yet didn't because they could not imagine what they would be without their job. I also knew some that basically died right after retiring, because they just didn't know what to do and their bodies shut down (lack of motivation to do anything as their mentality was, "if I don't have a job, I am nothing/worthless")
Picard's winery was traditional.
Sisko's cooking skills were traditional.
As for why people don't stay on Earth's utopia, or don't just move back there? Maybe they just don't want to. Maybe the want to feel like they earned what they get rather than have it handed to them. I run into people like that that insist they work for what they get even if they can get it free. A lot of the people that lived though the Great Depression seemed like that. Defined by their job regardless of how much money they had. They could have had enough to do whatever they like if they retired early, yet didn't because they could not imagine what they would be without their job. I also knew some that basically died right after retiring, because they just didn't know what to do and their bodies shut down (lack of motivation to do anything as their mentality was, "if I don't have a job, I am nothing/worthless")