Yes, I get all that. It's why a songwriting credit is worth more than a performance one.
The thing is, I don't really get much enjoyment from songwriting. On my own, at least. When I was playing in originals bands, I loved the collective songwriting process. But it's not something I really fancy doing myself. And that's OK. I'm happy working through the last 4 centuries of music. I'm currently playing baroque double bass pieces for nothing more than the enjoyment of doing so.
Which leads me on to the next point.
There's often antipathy to people who play covers, as if it's somehow artistically less valuable than playing "originals".
It's an interesting one. Most of jazz is (or was, if you're looking at the classics) technically covers, because they're reusing melodies and chord structures that someone else has written. In my band, we play new versions of old songs. They bear little relevance to the original (and we have a lot of fun). In some cases, it's much more artistically rewarding than playing in indie bands (or any other musical idiom where people expect you to conform).