How does one know it is unique if they haven't seen all of the others?
I take it you didn't catch the point about people looking at all the trillion other sunsets online. A lot of photographers from what I've seen take sunsets because their sunsets and it really shows TO ME. It's clear they just pointed and took the shot. No thought put into it.
I don't know what others see but it doesn't take a huge amount of investigative deduction from what's available online now to be confident that others who don't have a trained eye or aren't some simpleton just coming out of their cave that art appreciation is getting a tin eye due to information overload having to view a lot of crap and copies of crap.
It's really not hard to see whether a photographer or any creative person in communication arts has a discerning eye. I saw this in spades recently from an antique collector and interior designer who started a little shop around the corner in my small town. She and her husband travel around Europe making very good choices (like photographers should) buying furniture and collectibles artfully arranged in interesting compositions for patrons to browse throughout the shop.
It was a journey of discovery for me because I've never seen a lot of these items, especially the clever arrangements. I could see the talent and intelligence in this woman's decision making while most patrons just glanced around and left without a word with some complaining about the prices of each item and others taking random shots with their cell phone without any thought behind noticing these beautifully arranged compositions. I took 5 hours shooting this shop and I still wasn't done capturing all the interesting compositions.
Can a photographer show that they can make the same intelligent choices and convey that in their images similar to what this woman has done with collectibles? Where is the talent? Where is the source of the originality? The photographer taking the picture or the woman who created the compositions for the photographer to take notice while others didn't?