It was far more complicated than that, but I agree that most peasants in Southern Italy (and largely in the North as well) had little or no interest in Italian national unification and largely felt no attachment at all to any notion of "Italy".
So we agree that the southern proletariat will never revolt against their king to join the kingdom of Sardinia.
Without Garibaldi my bet is that the Sicilian secessionist barons will rebel against the Bourbons , and in trouble they'll ask help to the Sardinians which will have a pretext to invade and annex South Italy.
The papacy will be conquered like it happened historically