Why do you preach?

Historical Anabaptist (Brethren) belief is that the Great Commission has been fulfilled. At least, that is what the holders of this view say.

This is what they point to for support:

Mat 28:16 Then the eleven disciples went away into Galilee, into a mountain where Jesus had appointed them.
Mat 28:17 And when they saw him, they worshipped him: but some doubted.
Mat 28:18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
Mat 28:19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
Mat 28:20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen


Mar 16:14 Afterward he appeared unto the eleven as they sat at meat, and upbraided them with their unbelief and hardness of heart, because they believed not them which had seen him after he was risen.
Mar 16:15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.
Mar 16:16 He that believeth and is baptized shall be saved; but he that believeth not shall be damned.
Mar 16:17 And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues;
Mar 16:18 They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.
Mar 16:19 So then after the Lord had spoken unto them, he was received up into heaven, and sat on the right hand of God.
Mar 16:20 And they went forth, and preached every where, the Lord working with them, and confirming the word with signs following. Amen.


Col 1:23 If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard, and which was preached to every creature which is under heaven; whereof I Paul am made a minister;


Rom 16:25 Now to him that is of power to stablish you according to my gospel, and the preaching of Jesus Christ, according to the revelation of the mystery, which was kept secret since the world began,
Rom 16:26 But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith:


It seems that at least from a cursory reading of the text that that view is correct. Is it?
Is that the case, and in today's economy upon reading Matt. 22:39 we simply see "neighbor" in a larger scope because of better modes of travel and communication?
To me, if we are called to love our neighbor, that at least means that we should tell them the truth about their precarious situation before a just God, which in turn leads to "preaching the gospel and baptism" a la Matt: 28. Doesn't both roads lead to the same place, or are not those that are opposed to the Great Commission and those that believe it is still very much in effect both ending up at the same destiny - in regards to impetus for preaching...?