Why don't humans breed like bunnies? wouldn't it be more efficient to have lots of kids lots of times?

The human body is not made like the bunny because we are made to make 1 at a time whereas bunnies are made to make several

Because humans are complex. bunnies are pretty simple and relatively easy to mass produce and their young die off more often. it's better to make them well than too make a ton of bad ones.