Paul spent time in Arabia where God taught him the Gospel. He then returned to Damascus for three years before going to Jerusalem. And like Paul, God will often take us somewhere to teach us what we need to equip us for our future. Our service for Christ starts today. The call will come when we are serving Him, not to serve Him.
The local church needs people who are faithful. What would happen if everyone in the local church just got up and left? God will save people and place them in a local congregation of a church. It is within the local assembly that we build up, exhort and occasionally discipline and correct each other.
God does not save most people to send them elsewhere. The majority of a local church will be raised up to encourage, exhort and support the few that are sent out from that local church. We learn to serve within the local church. There is a difference between those who profess to be a christian, and those who participate as Christians.