Can Sunday School Reach All People?

In the Great Commission, Jesus commanded His disciples to "go and make disciples of ALL nations" (Mt 28:19, NIV, emphasis added). Why is the tool of the Sunday School, as it has been practiced, incapable of reaching all people? What limits it from reaching all people?

If Sunday School is only offered on Sunday morning, 40% of people cannot attend. They are the firemen, policemen, medical personnel, and other workers American society has come to expect. Vision and leaders appear to be in short supply. And current churches can't get remotely close to housing all people if Sunday School space is used only once and limited to the church campus.

What then is the answer? How can we lead church leadership to consider the need of ALL nations? How can we begin to offer Bible study at more times and places? How can we increase vision and leader enlistment and development? Are we stuck with ineffective Sunday School?