I take your point about the general structure of the Masses being different, but don’t agree that it’s a good or sufficient reason to restrict the use of one or another. Of course, a strict application of this principle would suppress the use of the Eastern liturgies, and I believe that very few people would be in favor of doing that. (Although the idea has had some adherents historically, as Fr Benson alludes to in his “Lord of the World.”)
If (and this is a very big “if”) the '62 Mass were to become as popular as the '70 Mass then it would be necessary for Latin Catholics to become familiar with two different rites of Mass. Some people might not like this, but it’s really just the situation we have had since '88 on a much larger scale. I’m sorry that you are opposed to the idea, but the decision is not yours, no more than it is mine (or anyone else’s besides the Holy Father). Do you think that the '88 indult should be rescinded entirely?
Realistically, while I would like to see the '62 rite more generally available, I very much doubt that we’ll ever see anything close to a '62 Mass in every parish. I can’t see leaving the choice to the celebrant of a particular Mass, willy-nilly, in any case. Some sort of system would have to be organized by the local ordinary, but hopefully on a more robust scale than is found in most U.S. dioceses at the present time. Also, I would hope that we saw some of the pre-Conciliar liturgical life in its fullness, and not just the Mass. Sunday Vespers (which is hardly available anywhere, in any rite) would be a good place to start.
The educational requirements for seminaries are laid out in the Apostolic Constitution “Sapientia Christiana” of Pope John Paul II, which was promulgated in '79. Section IV.24.2.3 says “A suitable knowledge of the Latin language is required for the Faculties of the sacred sciences, so that the students can understand and use the sources and the documents of the Church.” The document concludes “His Holiness John Paul II, by divine Providence Pope, has ratified, confirmed, and ordered to be published each and every one of these Norms of Application, anything to the contrary notwithstanding.” which is why I believe that the norms are binding. This may not be true in the U.S., or it may only hold true for certain seminaries (which grant the pontifical degrees?)
I agree that it’s possible that the '88 indult will be withdrawn, but I don’t think it’s as plausible as any of the other possibilities. The Holy Father, who himself celebrated the '62 rite at times while still a cardinal, seems sympathetic to those who would like to retain and broaden its use. Moreover, he has received one of the S.S.P.X. bishops, and seems to want to enable their reconciliation, if at all possible. Thus, I would argue that the most likely possibility would be a lessening of the current restrictions. Of course, he will not wish to ride roughshod over the diocesan bishops, but some concessions may well be required. I have no particular revelation of what will happen, but this seems the more likely option.
I’m not sure if you meant to disagree with my assertion that more people would flock to the S.S.P.X. if the indult were rescinded. I stand by that, in any case.