Speaking extra cathedra is to act like the old English kings did and to pronounce what has always been “law.” or as a Chief Justice might in deciding what is “constitutional.” I am as leery of the Ultramontanes as I am of the Gallicans,although not ashamed to call my self a papist.
According to your definition of papal infallibility: “Popes are only infallible when they are reaffirming what dozens of generations have affirmed,” a future pope will soon have to declare:
1. Artificial Contraception is OK.
2. Homo Marriage is OK and a valid sacrament.
3. Divorce and remarriage is OK.
2. Popes have never been infallible.
All of the above statements are presently being “affirmed” by the majority of the current generation of Catholics; and by your definition, a future Pope is obligated to eventually declare them to be true, right?