At the same time, can't this make it harder for members of the different teams to become friends with each other -- in a way, they are competitors, not coworkers. And maybe they'd be worried about getting fired if they "lost"? That could cause some of them to start looking for other jobs? Or some could feel bad, get demotivated. And other weird side effects.

What could be ways to avoid such things

How did this work out at Apple? When you were there