So Couchoud:57 As they were walking along the road, a man said to him, “I will follow you wherever you go.”
58 Jesus replied, “Foxes have dens and birds have nests, but the Son of Man has no place to lay his head.”
59 He said to Philip, “Follow me.”
But he replied, “Lord, first let me go and bury my father.”
60 Jesus said to him, “Let the dead bury their own dead, but you go and proclaim the kingdom of God.”
61 Still another said, “I will follow you, Lord; but first let me go back and say goodbye to my family.”
62 Jesus replied, “No one who puts a hand to the plow and looks back is fit for service in the kingdom of God.”
10 After this the Lord appointed seventy-two others and sent them two by two ahead of him to every town and place where he was about to go. 2 He told them, “The harvest is plentiful, but the workers are few. Ask the Lord of the harvest, therefore, to send out workers into his harvest field. 3 Go! I am sending you out like lambs among wolves. 4 Do not take a purse or bag or sandals; and do not greet anyone on the road.
The first apostles looked backward; they were unable to leave their household without farewell or to “hate father and mother” (xiv. 26), i.e., they were unable to shake themselves free of Judaism. That is why Jesus chooses new apostles.
(The Creation of Christ, p. 404, my bold).
Therefore it is clear the reason why Luke added the verse 10:2 :
In this way it is eclipsed the true reason to appoint 72 new disciples: the old 12 disciples had failed totally to follow fully Jesus.He told them, “The harvest is plentiful, but the workers are few. Ask the Lord of the harvest, therefore, to send out workers into his harvest field.
Mark and Matthew didn't image the same ''solution'' of Luke (the addition of verse 10:2) therefore they removed the entire mission of the 72 disciples from their gospels.