I think that if he shut it down, most of the SSPX priests would break out of the Conciliar Church again ... at least at this time. But they're working on changing those attitudes.
I disagree. Just look at the last 7 years.
Here is where you go wrong in your thinking. You are looking at the big picture, and drew these conclusions. It's an honest mistake. But here is why I think you're wrong:
It's not "A group of 300 SSPX priests leaving". It's an individual SSPX priest leaving, times 300 instances. There's a huge difference!
Each "SSPX priest leaving" is in isolation. He has his own influences trying to keep him asleep, his own fears/emotions, etc. There is no perfect communication between them, or hive mind. Each individual would have to seek out and join the Resistance, or set out to start his own little group/chapel as an independent priest. Most SSPX priests -- at least those STILL in the SSPX after all this time -- are too scared to do that. They don't have the inclination or personality for it, or they would be Resistance priests at the present time.Think: Fog of war. A lot of things would go differently in war, if everyone had perfect knowledge of the battlefield and the other side's resources, manpower, etc.Also Think: The audience has a different, BIG PICTURE grasp of the situation in a movie, compared to the main character(s) who don't have perfect information. Especially information about what the Bad Guy(s) is doing. Have you ever yelled at the TV screen?
Each would-be departing SSPX priest would have to deal with all the issues would-be Resistance priests have to deal with today: worrying about where they would go, who would pay their health insurance, transportation, lodging, etc. and they would be confused (whether willfully or through no fault of their own) by distractions like Fr. Pfeiffer's cult.
Just like Our Lord very wisely said in one of His parables: If they won't believe Moses and the prophets, neither will they believe if one rise from the dead. That is the Gospel truth! (literally!) Our Lord DID rise from the dead, and the unfaithful J**s still don't believe in Him.
Likewise, if an SSPX priest doesn't see a problem with the 101 changes, compromises and contradictions in Sean Johnson's book -- which is not exhaustive BTW -- one could come up with many more examples, if such were desired -- neither will they have a problem with the SSPX saying the Novus Ordo Mass, etc.
After all, they are OK with Vatican II. Being OK with Vatican II logically leads to the New Mass. It's that simple.