There was quite a contingent of mistaken and naive SSPX priests in the bosom of the SSPX as early as 2000.
These priests believed and taught: "the Tridentine Mass, as we knew and loved it, is over. The only future is a Hybrid Mass, as there are just too many Catholics born and raised on the Novus Ordo".
I first heard this from Fr. Doran in the early 2000s, and it shocked me a bit.
Where is Fr. Doran today? Part of the Conciliar Church. Specifically, in the Maronite Rite -- probably the most liberal of the Eastern Rites.
There was/is a whole contingent that believes that if we could just get "inside" Modernist Rome, we could convert them from the "inside". As if we're not part of the Church now. As if a small dissident group could have any effect.