Her own stuff versus doing covers

[profjohn]

Maybe you guys can enlighten me on something. I have the impression that most (all?) of the songs Stevie does on CDs and on tour she wrote. But it seems to me it would be easier to meet deadlines (a CD every 18 months is a rule of thumb I read somewhere) to mix in some covers of stuff you like. Why doesn't she do that (or more of that)? I'll bet it has to do with economics, i.e., you don't get royalties from other people's music. Am I right?