My first thought was that he was Jobriath, the first openly gay pop star, and the first mass marketed pop star. His album bombed horribly when it was released. He was name dropped for many years by people like Morrissey and Siouxsie Sioux, and many claimed he was better than Bowie, even though he never was. They could say that simply because he was obscure, which made him hipper, and most people weren't familiar with his music and couldn't argue. He was obscure simply because he was never successful, not because his record label didn't put any money into promoting him, which they absolutely did.
Fans tend to blame homophobia on his lack of success, but I don't believe Jobriath was ever any good. He wasn't terrible, but his songs were forgettable. And from what I know of him, he just gave up. Bowie had released four albums and had exactly one hit before he released
The Rise And Fall Of Ziggy Stardust And The Spiders From Mars, which finally made him a star. If he hadn't done that, he may have only been remembered as the guy who did that one weird song about the astronaut named Major Tom.
Here is an article about Jobriath, and the possibility that Xavier may be a nod to him, although I don't agree with the author that Jobriath was remarkable, or that he "should have been a superstar."
http://www.npr.org/sections/therecord/2016/04/04/472983364/gay-glam-comes-to-hbo