Pattern Recognition Addiction
That's what makes top down space combat so addictive. This type of game is ultimately a flowing dance of various patterns that a person comes to recognize and seeks to repeat the successful ones, giving them an actual chemical rush when successfully "pulling off one of the moves". It gives this type of game a long term appeal to those who get into it. People actually become addicted to these types of arcade games.
Which is one of the reasons base defense, capture the flag, and space hockey would be more popular than most would imagine:-)