Impossible to compare. Across the population different people are going to naturally have better fine motor skills and melodic sense while others have better mathematical and causality sense.
Also easier is a misnomer. I'd be more motivated to learn this piece than to learn quantum physics. Also how deep into quantum physics do we have to go? I passed my intro to qm class during my bachelor's degree but I'm not research grade.
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It’s not that difficult of a guitar piece, definitely a Newtonian mechanics level.
The playing is an athletic endeavor- mechanics of technique, muscle memory, visual and aural memory. Might as well ask whether being a starting forward in the NBA is more difficult than quantum mechanics - certainly there are fewer NBA players than people competent in QM.