"Among other consequences, the Motu proprio Traditionis custodes may have prompted, here and there, members of the clergy of the of the official (or so-called "conciliar") Church to turn to the Society of Saint Pius X. In some cases, priests (and even a bishop, in the person of the Ordinary emeritus of Chur, Mgr Vitus Huonder) have even decided to offer their cooperation the apostolate of the Society. [Umm, no, he was ordered there by Francis -SJ]

Just like if you girdle a tree (cut completely around the bark), the tree is dead. At least it's a POINT OF NO RETURN. The tree will continue to LOOK alive for a while: it will have soft, supple branches and leaves for months later, but no more sap can flow above the girdling point, where the cut was made. So it's "set in stone" or a done-deed that the tree is dead. It's just a matter of time before the death FULLY manifests itself.

With a chicken, death takes minutes after the "point of no return" (e.g., removing its head). With a tree, it takes months. The SSPX might take years (Rome wasn't built in a day -- and neither was it destroyed in a day!)

That is the state of the SSPX today. The girdling has been done 100%. The organization is fully doomed. Just a matter of time before all the chapels/policies/etc. fully reflect the fundamental shift that HAS TAKEN PLACE (past tense).

A bit of Trad 101 --

One of the foundational principles that Trads have held to SINCE THE BEGINNING is the following:

When you have a doubtful Mass/priest and a certainly valid one, you are OBLIGATED to go with the more certain one.
And, the Novus Ordo (and new ordination) are at least SUSPECT/dangerous/doubtful.

Now I'll admit that some Trads today are more "sure than they ought to be" when it comes to the validity of the New Rite of Ordination -- or the Novus Ordo Missae for that matter. But that is beside the point.

The FACT is that these things are at least DOUBTFUL, and there is a Catholic principle that one is not even ALLOWED to go with a doubtful path when a certain path exists. That goes for the liquid used at Baptism, your Mass, your priest, and everything else. We must always choose the more certain.

TL;DR (short version): Catholic morality does not permit us to be risk-takers when it comes to what Mass we will attend, or other important matters touching on our Faith and our salvation. On the contrary, we are commanded to be extremely risk-averse and conservative -- taking the safest path.

It's my understanding that one can't approach doubtful Sacraments even if a certain path does NOT exist ... except in danger of death, but someone can correct me if I'm wrong.  There's some debate, of course, about whether there's positive or negative doubt about various scenarios.