I don't really give a shit.
What point do you hope I concede to, exactly? That because some original works are highly-cliche and plenty of fan art or arrangements are of high quality, possibly even better than the original work, that deliberately piggybacking on existing works therefore has just as much artistic merit as making your own creations? Because it's not going to happen.
Marvel and DC have made all the good superheroes and anyone I could come up with would likely be similar to one that already exists: Guess I better just say to hell with it and just draw Spiderman then, right? Drawing someone else stuff is just as worth my time as drawing from imagination!
The fact is: No matter how much you spin it, you cannot claim creative ownership over a remix and that is precisely because it only exists thanks to a work before it. If you want to be a composer, artist, writer, etc. It makes no sense to place equal value on fan works — it really isn't any more nuanced than that.