Upvote:3
I know this question is very old but I thought it deserved an answer because the speculation is quite inaccurate.
Comino was inhabited up till very recently, probably up till the early 1990s. People just left because modern lifestyles require amenities that are not available there and commuting by boat just to go to work and send your kids to school is not very feasible.
Regarding the depopulation of Malta, it was the island of Gozo that suffered the depopulation, twice.