I've thought about if I ever became famous(and there is a very small chance of that happening) if I'd actually NEED to come out, and I've aid I don't have to. But if it did come to it, I'd feel like people wouldn't listen to my Music as much and my career would take some blows because of that minor revelation. Do you think I should?
I think there have been plenty of gay singers - Lady Gaga (bi), Adam Lambert (ok, I don't know if he's actually famous), half of the group Pentatonix, Freddie Mercury (ok, yeah, he was half in the closet, but people still listen to his music quite a lot). You can also come out to people around you without making a big deal of it in the industry. I think it's worth it to live an open life. There are also many gay and bi actors. So I would say yes. And you may get more advice in Coming Out Advice.
The reaction probably depends on the genre of music. It might not be prudent for hip-hop artists to come out, as that genre is generally misogynistic and homophobic. Some exceptions include Macklemore, who is not gay but is supportive of marriage equality. Yet he has been very successful. Pop music seems safer. George Michael, MIKA, Ricky Martin, and Jake Shears are openly gay artists yet still have successful careers. Then again, regardless of genre, some might not care whether or not they lose fans. When you come out on a large platform, as famous artists can, you can give a voice to those that are not out and about. And it's liberating. You don't have to hide your true self. For some, coming out trumps losing homophobic listeners.