In all seriousness, perhaps Cruise's interest in sci-fi is related to his beliefs in Scientology and that -sci fi plays much into their belief system related to Xenu and the end of civilization?
Probably not. I don't know if he has an interest in scifi per se, or if he simply realizes scifi/action films make money.
I don't care for either Minority Report, or War of the Worlds, but love Vanilla Sky, probably the only non-action scifi film he has ever been involved in. Probably why it didn't do so well too.