But it actually does, and there is a lot of data to prove it. When you have a big project and a bunch of teams, the first thing you build is boundaries / walls. Then you get to defining interfaces between interdependent services. And this frees them up to get hacking on their modules in parallel - without stepping on each others' toes. Communication would have definitely helped, but it is way easier for smaller teams to own and operate their services and try to get a big organization plough through a big mess.
That said, microservices are just one way to solve a problem, and not always the right way. But there is always a place where you would look at the problem, the organization that is tasked to solve it, and it would fit just right in.