Speaking only for myself and the other musicians I've known personally over the years, the vast majority of us "doodle" on our instruments, experimenting with sounds and just playing for the fun of it. Most of the guitarists I've known used this approach when writing songs. Playing for the feeling and for the mood can produce a lot of noise, but it sometimes results in a moment of genius. Some players regularly record their musical doodling just in case they tripped over something great.
The idea that musicians are too arrogant and/or stupid to experiment with music is grossly inaccurate. There is a difference between the discipline of honing one's technical skills and using those skills to express one's feelings. It's understandable that people who are unaware of the difficulty and complexity of learning an instrument might think that all we need to do is make noise at random to write music. That kind of experimentation only works after countless hours have been spent meticulously honing those mundane skills. To someone who is not a musician, those years spent practicing are nothing but wasted time. Musicians know it may take thousands of hours of practice to create a few seconds of great music.
Not all art forms require the same level of mental and physical discipline. Some are much more cerebral while others are highly physical. Some focus on minuscule details while others are "big picture" concepts. Using the standards of one art form to criticize the others is unreasonable and demonstrates an ignorance of the demands of the other art forms. For instance, I would never say that the only skills required in acting are looking good and preening in front of a mirror. As a musician, I have no way to know and appreciate the depth of skill and intelligence required to portray a character in a convincing manner. All I can see is that he's just standing there, reciting a few memorized lines. The only people we musicians know who get by solely on the strength of their looks are vocalists. (I'm kidding. Some vocalists don't look all that great.)
That assessment is insulting to actors because, in my ignorance of the art form and its disciplines, I did not see the same level of discipline and skill in their performance as we musicians put into ours. The fact that I don't see it does not mean that it's not there. It merely means that I lack the expertise and comprehension to fully appreciate it. In the same way, assuming that musicians are too arrogant or brainless to approach music they same way an actor approaches a role is failing to fully appreciate the musician's art.
In my opinion (there is a great deal of room for disagreement here), I think this comes down to a philosophical difference. If we operate from the point of view that says that life is complete chaos and order is an illusionary cage, our artistry will elevate emotions over intellect and logic. We will gravitate towards random paint splatters, accidental noise, and mindless spasms. On the other hand, operating from a point of view that values order over chaos will reverse these approaches. Extreme focus on order may result in heartless realism, devoid of any emotion. Music may be mechanical and dull. Most of us will fall somewhere in the middle along this spectrum. Some of us may drift more towards order than chaos while others may run the other way. Wherever we are along this continuum, we may not agree with the philosophy of other artists, but we can respect their right to their own opinions and values. If we think that other artists are not listening to us, it doesn't necessarily mean they didn't listen. It could mean that we didn't get the answer we wanted to hear. I think we should have a little humility that says that, while I can share my values and thoughts with another person, I cannot choose those values and thoughts for them. Any attempt to push my values on another person will meet resistance. Complaining about that resistance may say more about me and my desire to make other people see things my way than it does about the other person.