It recognizes that there may not be a visible Head of the Church - hence, sede vacante. Otherwise there would, in fact, be an orthodox unity surrounding the Pope somewhere. There isn't. Not even the Novus Ordo has orthodox doctrine stemming from V2. Each diocese has its own set "orthodoxy".
Ok, you say it opines there may not be a pope, which also means the pope may well be pope. Not sure, but I don't think most sedes would agree, I think that most sedes are quite sure the pope is not the pope - at least sure enough to split and start their own communities.
But regardless, what is accomplished by the splitting away from established and growing trad groups in order to establish their own, separate chapels, seminaries and so on?
Is the sedeism idea more necessary than unity?
"In that day, saith the Lord of hosts, shall the peg be removed, that was fastened in the sure place: and it shall be broken and shall fall: and that which hung thereon, shall perish, because the Lord hath spoken it."
[Isaias 22:25]
Yes, and.....
"Woe to the pastors, that destroy and tear the sheep of my pasture, saith the Lord.[2] Therefore thus saith the Lord the God of Israel to the pastors that feed my people: You have scattered my flock, and driven them away, and have not visited them: behold I will visit upon you for the evil of your doings, saith the Lord." - Jeremias 23:1,2