The meta game is always changing, and probably geographically different.
At the local store championships we had no squadron with more than 4 ships. Many ran only 3 ships.
Now, I know that I ran 3 in part because I hadn't played much in awhile and fewer ships means fewer decisions and thus I could play faster. Plus it would be less cognitively challenging over the course of many games.
But why is the swarm so rare? There is still strength in numbers.
Is that they are too hard to fly well?