Thank you for question on why hasn’t Christ come.
The Gospel has not been preached in the world especially in the third world countries. People groups have not been reached for Jesus Christ.
It is estimate exactly how many people groups are in the world today but the best guess, calculated by Joshua Project, is 16,543 people groups. Out of these, there are 6,701 unreached – that is 42.1% of the world’s people groups that have never heard or accepted the Good News of Jesus Christ (Missions College – Bethany Global University). That is a lot of people.
The Great Commission is still unfulfilled.
For more perspectives:
https://www.quora.com/Why-hasnt-Christ-come-Has-the-gospel-not-been-preached-everywhere