Why doesn't my character/universe/profile sync between computers? [closed]

The short answer is that Starbound does not implement the Steam cloud save functionality, and thus no syncing can occur.

The more detailed answer is that a single Starbound "save" is actually quite a few files. There's the player file, of course, which saves your equipment and your ship info, but each individual planet also has its own "save file" where all changes that you have made (mining, tunneling, building, NPCs, etc.) are stored. The more changes that are made by the player on a given planet, the larger the file for that planet gets. Since there's so many available planets, it's quite possible for a single "save file" (meaning player data, ship data, and universe data combined) to be very large. It just gets too bloated to sync efficiently, so Chucklefish decided not to include that feature.