Either a laying of hands or annointing refers to consecration, and both are mentioned in the Acts and some epistles. Indeed the scripture does not mention, at least to my memory, consecration of every apostle, but it does not mean it did not happen.
It is also true that the disctinctions between bishops, priest and deacons were formed a generation or two later. The Greek "presbyteroi" most widely used in the New Testament is most naturally translated as priests, but the Protestant translations prefer the jejune "elders", another reason not to read them.
If you look at Titus you will find that Paul uses the term elder and bishop interchangeably and says he appointed Titus as an elder to Crete. The only laying on of hands that Paul received was from prophets and teachers at Antioch, not Apostles or bishops, along with Barnabas. Was Paul a bishop or not?
Paul in Ephesians sets out the offices given to the church to equip the saints for the work of the ministry. They are Apostle, Prophet, Evangelist and Pastor/Teacher. He does not mention bishop but he does add in other writings deacon, elder and bishop, but none of these are said to have any authority over the other offices.