Movies are a better example of a medium getting bland, but there is a material reason for that; production costs vs return on investment leading to less riskier films being made.

Music doesn't suffer from that same problem, in fact 'good' music can be made for nothing except the composer's time.

If you are looking at the kind of music that makes it onto Top 40 radio stations, then this is undoubtedly true. But that's not what is meant when you say

> For the past 30 years music has definitely become more "bland"

When you suggest that, you appear naive and ignorant. Because it means you don't know about Tyshawn Sorey [0], Mary Halvorson [1], Anthony Braxton [2], John Zorn [3], etc.

Pop music, a tiny sliver of all the important music being composed and performed today, has gotten progressively shittier. Fine, I'll grant you that. But who cares? That's not what we're talking about when examining the vast complexities being propagated and explored by today's musical masters. We are in a golden age of harmonic and compositional innovation.

[0] https://www.youtube.com/watch?v=Rqw-HE9szrs [1] https://www.youtube.com/watch?v=PEfK0ZfbLRA (featuring Nels Cline, who is actually much more important for his participation in the NYC avant-garde than for his involvement with Wilco) [2] https://www.youtube.com/watch?v=HNJfU0AJK2c [3] https://www.youtube.com/watch?v=RYis3q0vv7g

Many people who listen to classical (in the more general sense of the word that encompasses baroque and romantic eras as well) dislike folk music as being too simple. They are listening to harmonic complexity - the changing of chords over time. Irish music usually has two or three chords repeated in a predictable pattern. But it has micro complexity - subtleties of emphasis, timing, melodic variation, grace notes, etc. - that make it, to my mind, far more complex than it is given credit for. These intricacies are particularly difficult to measure objectively.

Other kinds of music, like EDM, rap, etc. have rhythmic complexity. Fans of this music often think classical music is boring because classical tends to be rhythmically predictable.

Within classical music, there is Classical (Mozart era), which values balanced form, strictly following structures like AABA, with the complexity hiding within the endings and transitions between repeated sections.

This is very different from baroque (Bach, etc.), which often has rambling forms, and lots of micro complexity - dazzling changes of chords and keys, very intricate harmonies.

I won't even go into modern "serious" music, which stretches the definition of music to its breaking point.

The point being, there are as many forms of complexity possible as there are variables you can control in creating a piece of music.

I suspect this actually brushes up on fundamental limits of measuring complexity such as the Halting Problem in a currently only vaguely defined sense.

Edit:

To give a more direct listing of variables an algorithm might want to attempt to measure complexity in, off the top of my head, we have:

Chords, melody, polyphany, timbre, phrase structure, rhythm, rubato, dynamics, movement/song structure, whole piece/album structure, rhyme scheme, assonance, alliteration, onomatopoeia, vocabulary size, word repetition, references to other musical or verbal phrases in other works...

I mean, people get PHDs in analyzing this stuff.

Edit again:

Here's one really specific example that highlights both the fun and difficulty of doing this stuff algorithmically: there's a piece Bach wrote where one person reads the page right side up, and the other reads it upside down (starting from the other end, all notes inverted), and it works out. Noticing patterns like that would take a highly sophisticated algorithm akin to what is used to analyze genetic sequences.

First of all, I don't like the term "bland", because it implies a judgement. I think a better word is "sparse".

But now, the question, and the thing the researchers got fatally wrong is: does sparseness really mean less complexity? When you phrase it like that, it sounds obviously silly, to me at least. You wouldn't judge say Picasso for not using enough colors, and complain about it being so bland. To continue on that path, Picasso only works because you know what things actually look like. Instead of having to painfully spell out every last facial hair, he relies on you knowing what a human looks like, and uses the space gained to express his intent more clearly. In comparison, older art might seem boring and predictable. I already know what a face looks like, why waste space showing me?

Modern music works on a similar principle. The sparseness of modern music is enabled by listeners familiarity with other music, which enables composers to simply sufficiently imply their intent, letting our brains fill in the rest, making space to innovate in other areas of the music.