What is the role of talent?

After reading your question, what comes to my mind is the idea of relativity and group consensus. I call my work "art", and luckily others in the art world may also. Likewise, they consider my abilities as having "artisitic talent". Now, comparably, my friend who also makes art may have less talent though he tries just as hard to expresses himself artisitically. He is still happy with less talent cause he enjoys the process and is not interested in comparing his talent. It's all about the passion.

The impact of talent is that artists express themselves in ways that stimulate the works' recipients. To be sure, nurture contributes to this ability, just as nature does. But if artists don't have natural talent, their works will fail to inspire anyone except the artists themselve.

As to the second half of your second sentence, it is simply a fact of life that most art ever produced is gruesomely bad. Just because everyone can express themselves, that doesn't mean everybody should. Personally, I'm quite grateful that society has watchdogs who take it upon themselves to suppress bad art.

How does talent represent a hierarchy that obstructs people from expressing themselves?

You like the idea that anyone can express themselves and so they can...with or without a great deal of talent.

Not everyone who expresses themselves can make a living at it, nor will they all be taken seriously, and only a very few of them will produce works that others will enjoy or value.

I fail to see a rational quandry, and shudder to think of what might be considered a solution for the irrational one.