This is going to start off sounding off-topic, but I promise it's not. My mom was (before she retired) a high-school English teacher, and when she taught poetry, she used the following analogy: Imagine a game of tennis between top pros, how exciting and energetic it can be. Now imagine that same game, but remove the white lines on the court. Now remove the net. What do you have left? Just two guys hitting a ball back and forth. What she was trying to say was: the lines, the net, the rules---they all give structure to the game. There's plenty of room for creativity within that structure, but without the structure, the whole thing sort of loses the point.
Now, tennis is a competitive activity, unlike music. I get that. And in poetry, there's such a thing as free verse, and I get that, too. When you create a work of art, you don't have to follow the so-called "rules" if you don't want to. But the rules can be helpful. They can establish context, offer guidance, provide structure. As a jazz musician, I rely on the rules all the time, because I'm making up music on the spot together with other people who are also making it up on the spot. Without a common language, a common understanding, it would be chaos. We need at least some rules just to keep the whole thing from spinning out of control.
Don't forget, too, that the rules aren't handed down from God---they exist because musicians have found over time that certain things work well. Many many Beatles songs have the same verse-chorus-verse-chorus-bridge-verse-chorus form. Is it because John and Paul weren't creative? No, it's because they found something that really really worked for them. As many people have noted, Mozart and Haydn and Beethoven (earlier in his career) all wrote pieces with essentially the same form, later called "sonata" form. But at the time Mozart was composing, he didn't know about sonata form, he just knew that certain things worked for him---it wasn't until much later that people like Czerny analyzed his music and found the same forms used over and over.
Beethoven is actually a great example here: In his earlier career, he followed the forms of the master composers he admired the most, namely Mozart and Haydn (in fact in his early twenties he studied with Haydn). As he got older, he found that those forms didn't work as well to express what he was trying to express, so he started diverging from them, and at first he encountered some resistance from audiences who thought he had lost his mind. But his music was so compelling, so full of intelligence and feeling, that eventually they came around. Towards the later period of his career, he was trying some really wild stuff, but it worked because he absolutely knew what he was doing.
The point is: of course you don't have to follow any specific musical forms if you don't want to. But that doesn't mean you can't be creative within a form. And in fact you may even end up creating your own musical form(s) without even knowing at the time that you're doing it.
Addendum: On Aesthetic Value
After re-reading your question and some of the comments, I feel compelled to elaborate on something. You say:
Isn't it true that we only create music, because of its aesthetic value?
The answer here is a resounding "Yes, but." What is "aesthetic value"? I get the impression that in this context, you understand aesthetic value to mean just "it sounds pretty". And that's fine, I suppose, but it's not what I mean by aesthetic value. You say people
might like [a piece of music], only based on its aesthetic value, not based on its musical and technical analysis
but I find the technical and musical aspects to be just as important to my overall sense of the aesthetic value of a piece than simply how pretty it sounds. These aspects increase my understanding and enrich my appreciation for a piece of music. Indeed, one can find great aesthetic value in music that one finds kind of ugly-sounding.
Look, you're a programmer, right? Imagine you have two pieces of code, both of which have the same functionality, but one of which is spaghetti code and the other of which is clean, well-organized, modular, all that good stuff---well, there's aesthetic value to the latter code, isn't there? Even if the end result is the same? The end user may never know the difference, but anyone reading the code would see right away that one has greater aesthetic value than the other.
My point is: there are aesthetic values to the technical. There can be great beauty in the way that a composer handles the problems posed by a particular musical form. If you don't want to feel constrained by a particular musical form, well, no one is forcing you to write music a certain way. But there is (at least, there can be) a lot more to music than simply how beautiful it sounds.