As Father Pfeiffer has said, "God will provide." Only God knows at this point what He will provide, and how it will affect the seminary in Boston. It could be the support of the two resistance bishops, or it could be another, as of yet undetermined Bishop, or it could be plane tickets for all the Boston seminarians to go to France.
Yes, God could create a bishop
ex nihilo or from the slime of the earth, but He probably won't. (Actually, since Our Lord founded the Church, and the way new bishops are to be consecrated -- in an unbroken line, all connected to the 12 Apostles and Peter -- wouldn't God be contradicting Himself if he created a priest/bishop with no Apostolic succession?)
I personally don't believe in "perfectly good Trad bishops who were just unknown or hiding for all these decades".
No, it's common sense that Traditional Catholics have been looking for good priests and bishops in every nook and cranny for the past 45 years. If any were out there, they'd be found by now. Especially in this age of the Internet.
Another "trad bishop" appearing out of nowhere is what they call TOO GOOD TO BE TRUE, which is precisely what happened with the Ambrose Moran situation.
Imagine a lunchroom full of children. A terrorist bursts through the door, and starts shooting the children one by one. Everyone hopes that one of the adults present in the room will heroically try to neutralize the invader. With every passing minute, every additional dead child, the chance of a Hero saving the day goes down exponentially.
Here's why: If a man in the room won't be the hero after 10 dead children, after 15, after 20, what chance is there that he'll do something after 25? He would have to explain to those 20 sets of parents (of the 20 dead children) why he sat and did nothing! Either has "has it within him" to be a hero, or he doesn't. After the first 20 children are dead, it would be MORALLY impossible (not physically impossible) for any of the adults to get up and be the hero. They are already set in their decision.
Replace dead children with dead souls, cafeteria with the Catholic Church, terrorist with Modernist, and a shooting gun with spreading error, and you see what I'm getting at.
Now you might object that maybe the man needed 10 minutes to "steel his nerves" and work up the courage to act -- which unfortunately cost the lives of 50 children in the meantime. True enough; so this comparison limps on that point. However, in reality, any good bishop has had FORTY-FIVE YEARS to think, pray, study, meditate, and make a decision. Think of how many good and bad days, days of energy and days of sickness, he has had during a period of forty-five years.
If he hasn't come out heroically supporting Tradition yet, HE'S NOT GOING TO. Period.