Box office Cruise is typically immune to couch jumper/scientology Cruise, but if it's true and he came out about it, right or not, it might affect the parts he's offered. Maybe those heading these movie studios are older, crotchety men who aren't as progressive when it comes to homosexuality as we assume or hope people in the year 2015 are and are becoming.
Hopefully that's not the case, but maybe they think a percentage of their audience just large enough to consider wouldn't go to their movie if the lead was gay. There are a lot of ******* morons out there in this land of the U.S.A. guys! They go to the movies just like the rest of us, so studio execs might not think they deserve
to be thought of, but from a business P.O.V they're consumers of the product movie execs are selling just like everybody else. This is pure conjecture, who knows. I hope I'm wrong about being cynical about a certain faction of our country.
If any of what I just said was true, then it would be less of a risk for Cruise, himself, to wait until he's at a point of his career where he's in a supporting actor role opposed to the lead.