Well, either you're wrong...or the churches you go to have some extremely tired, stressed out pastors!

Because a small group of, say, 5 people can't run an entire church by themselves. They need the woman who runs the daycare system and daycare staff (a leader); they need the worship leader (another leader); they need the youth leaders to help the youth pastor out (also leaders); they need the Bible study and small group leaders to oversee the every day spiritual needs of each of their small little groups (more leaders); they need people to initiate, head up, and lead service projects in the community (leaders); and much more. Call those people by any name you want, but they're still leaders in the church. They have small leadership roles, but they still lead something and some people. And they're still vital to the body of Christ.
I dunno, maybe you come from a tiny church or something. Perhaps a church of 20 members is fine with just a pastor, associate pastor, and youth pastor leading everyone and everything, but more than that and those people just can't handle that amount of work.