In order not to be vagus a priest has to report to a superior (usually a bishop, but not always) WITH JURISDICTION. News flash: all Traditional priests are currently vagi except possibly the FSSP (if you think they count a Traditional priests). Reporting to some random bishop who has no jurisdiction doesn't count. And the FSSP superior has never been a bishop (deliberately), so the priests reported the FSSP superior and merely had various friendly bishops perform their ordinations.
In that case (which might be true), then the technicality of being a "vagus" doesn't matter, and what matters more is the SPIRIT of vagary.
Let's put it this way: There's no way that a priest like Fr. X or Fr. Y (names withheld) who chose to heed the siren song and went off to "be their own boss" are every bit as good/promising/holy for parking your soul (and those of your family) as a priest who seeks out and submits himself to a good Traditional bishop who is doing God's work -- fighting the good fight.
Which priest is more in keeping with the spirit of the Church, the spirit of his vocation, the spirit of the Priesthood? Remember, FUNDAMENTALLY a priest is a bishop's helper, full stop. A priest who makes no effort (or makes excuses) why he can't submit to one of the MANY TRAD BISHOPS doing God's own work -- such a priest is GOING to be inferior and have issues at the very least. His whole apostolate will be flawed by his pride, willfulness, and lack of obedience.
Remember how God works. He doesn't need one more priest. He doesn't need ten more priests. What He wants is JUST A FEW holy priests completely surrendered to His Holy Will. Always seeking and trying to do God's will. That's all God "needs" from Trad priests. The idea that a priest can work better off on his own -- that's a delusion of the devil. ALWAYS.
Just because the Novus Ordo happened doesn't mean Obedience is obsolete. Obedience is STILL extremely important, especially for a priest. Especially if he wants his apostolate to bear fruit.The letter of the law killeth. The spirit giveth life. The Pharisees were masters of keeping the
letter of the law.