You are a fool if you think Bungie didn't purposely make enemies and chest respawn so quickly. Imagine if after all enemies are killed they don't respawn for 10-15 minutes, same with chests. The game would be pathetic, why? Because on your arrival to a planet you would find nothing as the team that was just their 2 minutes before you wiped and took everything. Now you have another 13 minutes of sitting around doing nothing waiting for things to respawn so you can do something other then look at the scenery