Right, but as you so clearly stated, RTS don't have Death Penalties. RTS and MMO's are completely different on many scales. This isn't a build-your-defenses game where the only penalty IS death (game over). MMO's require strategy for a number of reasons:

1) To complete the mission
2) To receive the gear you want (if fighting a boss)
3) Time Saving
4) To prevent death and it's penalties.