Consider that technology has made it unnecessary for humans to work or trade much at all. Ships clean themselves...maybe all buildings do. Ships can perform automated repairs...maybe all pieces of technology (communicators to whole cities) can repair themselves without manual support.
No one goes hungry, thirsty, cold, or uneducated given replicator and computer interfaces. No one needs to leave a planet, or in some cases a room to see arrays of wonders that would shame our greatest explorers. Ships can navigate and repair and run themselves with no crew save one to command them - I wonder if there are AI contingencies for what the ships are to do in the case of the whole crew being out of commission.
People aren't all that necessary to keep this level of technology, of society, going. They are freed up to contemplate things. And they play and fiddle with technologies to understand them so as to make better versions.
Perhaps people are leaders, innovators, researchers, and occasional specialist...where the transporter may need a cheif there to work some artful science the machine can't automate.
It seems to me though that that life is pretty swank, and that traditional employment vs. traditional consumption dynamics will be different here.
Hell, Trek doesn't even address the very real world AI's that'll be everywhere, and our eventual immortalities plugging in to benign Matrixes and Collectives.
...Economics will change - lets just try to remember to change them for the better. New economies, like all new frontiers are settled and acted upon by both saints and sinners.