John Paul II need not lose sleep worrying about any future pope overturning the excommunications of Marcel or the decree of schism against SSPX. The SSPX may evaporate or its adherents may recant and repent and do penance for their crimes and those of their excommunicated leaders and schismatic forebears, as the case may be, in which event, the Catholic Church will, no doubt, consider their re-admission.
SSPX. Something about a flea, an elephant's leg and a yearning for an indecent act.
Succeeding popes can supposedly overrule "Quo Primum", but they can't lift the alleged "excommunication" of Archbishop Lefebvre by John Paul II?
I'm convinced that you do think this pope to be a god.