The only way to separate the issue of Tradition from the issue of Authority is to grant the universal indult. As long as the Mass of the Ages goes in catacombs, the SSPX will be forgiven by many for its insubordination. And those are the many who the Vatican should listen to the most, unless they want the cafeteria to reopen. On the other hand, if the indult is granted, SSPX remains with the marginal issues of ecumenical policy and maybe the extent of Papal authority.
If the Tridentine Mass is restored, the schism has the wind taken out of its sails. If not, we have another orthodox church spinoff in a generation or two, because the schismatics have a legitimate complaint.