As long as we're fervently, actively, and vigorously pursuing the Resistance in the meantime, +W's advice is the best Catholic advice. It depends on what you consider a "given".
For me, pursuing the Resistance as we have been is a given. That is, supporting faithful priests (that is, those in the Resistance), setting up, maintaining, and supporting alternate "Resistance" chapels (as opposed to the old SSPX chapels we used to attend/support), speak out to everyone online and offline about the machinations of the neo-SSPX and how it has changed, etc.
While Resisting, we can meanwhile hold out some (supernatural) hope for the SSPX, and prayers are certainly never wasted. Let's not become our enemy, after all. The whole point of the Resistance is to stay Catholic along the lines of +ABL, who was faithful and Traditional as well as charitable and Catholic.
If we lose that, we'd fall from grace every bit as much as the SSPX did. Just in a different way, that's all. Remember, the devil doesn't care how he gets you: Giving up the fight and joining the local Diocese? Fine. Going extreme in the other direction, becoming bitter, and becoming another Dimond Brothers? Also fine. (from the devil's perspective)