NOTHING done after about 1900 is "original"...all the ideas were shot in the first six decades. Nudes? Alllll derivative. Allllllllll just "imitations" of what was done before. Portraiture? Allllllllll nothing more than imitation. As he writes, if one just stays on the bus, soon one will discover that one has made one's very own way in the world.
When playing the guitar, I sometimes think: "damn, this melody is probably already been made by someone else before... have to think about creating something different."
Maybe all melodies already been made multiple times, ... or if not: when will be this day, there will be a break even point where all things are already made?
Wouldn't think this kind of creativity is unlimited. But at some point, some combinations of rhythms, melodies, speeds, chord progressions will all have been made.
You will have this kind of stuff with photography too... if the same composition, model, viewpoint, position, color, bokeh,... is already been done once...
Staying in your own world or bus, is the best thing indeed. Not listening to other music to get influenced, not looking to other pictures at all ... let your own ideas flow.