When you're working inside a single team, alignment isn't hard. You just know what others are doing and when you don't you just ask. It's not too hard.
When there are multiple teams, it becomes a bit trickier. Each team has their own direction. However, try to add partners and suppliers. Each with different motivations and incentives.
Think about it this way: 2 teams want to integrate. Half way through you find out that one team is building a bridge and the other is building a tunnel. WTF is a common reaction. The overall conclusion is that someone needs to take charge.
Then we come to the following common misconception:
Complete alignment - teams do whatever the leader says.
Complete autonomy - teams do whatever.
Alignment enables autonomy.
There are multiple ingredients required to reach alignment at scale.
One wild question pops up: What are you working on and why?