Why wasn't Steppenwolf's John Kay successful as a solo artist?

I know there are some fans of Kay's solo work on these boards, but why do you think he really didn't do a whole lot as a solo artist? Do you think it was because his solo stuff wasn't real hard rock so the Steppenwolf fans didn't dig it, and his country stuff didn't register with country fans thinking "John Kay, he's hard rock"? I personally think his solo stuff was/is great, and he had a mild hit with his remake of "I'm movin' on".

I remember seeing once where Danny Sugerman said "people weren't as interested in him as a solo artist, but as Steppenwolf yes, it didn't matter who was in the band as long as they played "born to be wild". I guess he was stereotyped as so many artists are.....