Lots of scrutiny doesn’t mean they’re complex, it just means there’s interesting stuff there. I can reduce whatever the hell I want. Not all great are is complex, that’s a frankly stupid misuse of the word complex. All great art is well executed, not everything should be complex. Many things work because they’re simple. One of my favorite examples is the bridge in the song “Bad Company” by the (mediocre) band of the same name, it’s one of the most awesome bridges in the history of rock and roll, it’s also 3 simple chords and any 1st year guitar student could play it. Often times adding complexity makes something worse, again I’ll stick to rock and point to Yngwie Malmsteen. On a technical level one of the finest guitar players to ever walk the earth, and he cranks out unlistenable tune after unlistenable tune. Because he’s so addicted to his own talent and his ability to lay down complex guitar lines nobody else can play he never stops to actually give the listener room to listen, or make things cohesive and harmonic.
Great art has to touch people’s heart. And often times the best way to touch people’s hearts is with simplicity. There’s a reason everybody knows the beginning of Beethoven’s 5th and serious classical music nerds know anything after the first minute or so. The beginning punches you right in the face with 5 simple no screwing around chords. The rest is still quite good, but it’s too complex for the average listener. That beginning though is so wonderful in its simplicity it’s the basis of all power chord rock. That simplicity resonates through history where complexity gets lost in the shuffle.
As I said, complex doesn’t always mean good. There’s a composer named Max Reger who wrote heavy, contrapuntal music that impressed pedants but didn’t have the content to justify the complexity. As opposed to say Bach. But Nabokov put it well when he said he would mark down any student of his who would write something like “Great art is simple and honest.” Great art, he insisted, is complex and deceitful. Beethoven’s fifth is a great example of a very simple ‘plot’ (the thematic material) being a great whole because of what is done with it.