Why didn't Moon lander have a streamlines shape?

Space, and the Lunar surface, are a vacuum. There is no air, so no need to streamline the craft to prevent air friction.

Another thing a lot of people don't know. here on earth, as a rocket climbs, it seems to be on top of a pillar of fire. That is because the air around the rocket exhaust doesn't get out of the way fast enough for the exhaust to expand.

In space, there is no air to hold a column of exhaust together, so the exhaust sprays out widely. This is one of the reasons that no Apollo lander dug a crater beneath itself. What exhaust was still coming out was too widespread, too high above the surface... and the surface consisted of hard rock under a thin layer of dust. It would be like expecting a leaf blower to tear holes in your sidewalk!