Since bishops were only present at the time of Paul, and no bishops were ordained after Paul.
It’s a minority view held by certain groups of radical Protestants. I have had long, friendly conversations online with an adherent of one of these sects. Their argument can be summarized as follows:
(1) Any true Christian church must be strictly modeled on the New Testament, by which they mean the specifications listed in the Pauline epistles.
(2) A true church has no ordained clergy. In the NT, only Judaism had priests (
hiereis). The NT churches had apostles, elders, and overseers (
apostoloi, presbuteroi, episkopoi).
(3) There were no more apostles after those named in the epistles. Titus, for instance, cannot correctly be described as “the first bishop of Crete,” because he was an apostle who was never replaced by a successor.
(4) Elders and overseers are members of their local communities who are elected or appointed to those posts by their fellow members.
I see it as a kind of time-warp ecclesiology. They are pretending that, since the day Paul wrote his last epistle, there has been no further historical development of Christian institutions. In particular, they regard “Constantinian Christianity” as a terrible mistake committed by Pope Sylvester.