Just go back in time to 1946 and alter the outcome. Instead of having to leave Umberto II remains on the throne. History would most likely have gone like this:
crown prince Vittorio Emanuele meets a Marina Doria in the sixties and marries her in 1971 (think of Harald of Norway or Carl Gustav of Sweden). He succeeds his father in 1983 or even earlier if there was an abdication.
The new crown prince Emanuele Filiberto marries French actress Chlotilde Coureau and they have two girls.
Had the line of succession not been altered before it would have been altered at that time to allow their oldest daughter to one day succeed instead of a distant cousin.
This is absolutely in line with what happened in reigning dynasties and would have happened in Italy had the monarchy continued. Even had the Italian politicians been in favour of keeping the male line European pressure would have forced them into allowing female line succession.
The same would be the case for France had one of it's monarchies survived to this day.
Obviously the “moron gene” remains quite dominant in the Savoy senior line - into a third generation now...
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