The necessity/possibility of managing taxes and industry on every single planet is called micro-management. Too much micro-management can make a game un-playable, while too little will make the game too simple or unrealistic.
VGAP offers a level of micro-management which is "just right" for most of us. Although it's still manageable to do everything by hand, many players use tools like RandMax to help them. This way, the tool does most of the work, but you can still intervene if you think you have a better way of managing a planet.
