Due to the high cost of base components, players are encouraged to form groups and work together. This has a two-fold positive effect. From the perspective of the players, it makes the game more fun by encouraging relationship-building, co-operation, and friendship, thus providing a social component that not even most multi-player games have. Furthermore, players will likely communicate with each other outside the game environment (using email, chat programs, etc.) and encourage each other to play more often, which means more revenue.

SolSys Developers' Site