Do you really think that?
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.
Or things would have gone differently.
Exiled king Umberto refused to accept his sonīs choice of a bride.
He did not even attend his marriage.
Do you think a reigning King Umberto would act differently and accept such marriage ?
Or a Crown-Prince of a reigning monarchy would do the same ?
I don't think VE and Harald are chip of the same block, although I must recognize Marina Doria has always acted in a most dignifying way.
Think the way she tried to appease things in Madrid and apologise for her husband stupid behaviour.
And C-G is not comparable to V-E or Harald since he married when he was already the king and had nobody to give satisfactions to.
If Italy had remained a monarchy, I believe V-E would have married someone else than Marina or have to step back and leave the way to the Aostas who always had a good relation with K.Umberto.
I agree that if both V-E and E-F had married with the approval of the reigning monarch and E-F only had fathered these two daughters, the law would have been changed as has in every other other reigning monarchy.
The problem is that Italy is not a reigning monarchy.
Think of Roumania and how King Mihail felt he could not alter the succession law.
V-E thought otherwise.
But if V-E and Harald are not chip of the same block, V-E and Mihail are not chip of the same forest