(Ethan's view on) The man who played the violin

In a commonplace environment at an unexpected hour:

Do we perceive beauty?

Mostly not. Notice how in the story, the woman perceiving the beauty of Bell's performance has already seen him playing in a sophisticated place. Notice how the interviewed people, who said Bell's performance slightly interested them, had experience in violinistic music, like the man who focus on becoming a violinist but gave up.  The 3 year old kid who was interested in the music playing hasn't become numb to experiencing street musician performances. I would say we perceive beauty that we have knowledge on, or perceive beauty because the perceived entity is unique to us.

Do we stop to appreciate it?
Yes, we do. We barely appreciate it, but out of the many people circulating the area there is always at least someone who will stop to appreciate talent. People are unpredictable, and because there are so many of us, humans are bound to notice talent of any sort.

Not all of us. Some
Do we recognize the talent in an unexpected context?
Not really. You can see that there are some people who recognize talent in ordinary places, but most of us largely recognize talent based on context. It makes sense that we wouldn't usually see beauty in a unknown violinist playing inside a plaza, because the plaza and subway stations are places where we go to head to work, purchase goods and services, or have somewhere else to go. This is why concerts are planned in grand places, why musicians wear fancy attire, and why first impressions are important. We don't recognize talent in unexpected places because our instincts tell us to focus on our task and view the new person as ordinary because they look normal, they look like they're doing the typical street musician , and is playing violin in a public, normal place where one goes to work.
If we do not have a moment to stop and listen to one of the best musicians in the world playing the best music ever written, how many other things are we missing?

I don't know. Sometimes we miss something grand because we don't see it as grand. We could be missing amazing things, but we could also be missing typical music played by street musicians who actually need profit. That's what's hard about recognition: you don't know what is grand and what isn't until you closely observe or someone tells you the person is amazing.