Usher is an R&B legend with more classics than any other artist his age. His catalog (minus the last 2 albums) is pretty much flawless. The Confessions album went Diamond and he was pretty much the biggest artist in the game at one point. Back in the 90's, everyone wanted to "dance like Usher" or had Usher posters on their walls. He was able to adapt at the start of the 2000's pioneering the futuristic Neptunes sound to R&B and later adapting and pioneering to the crunk sound with Lil Jon. Being adaptable is the key to longevity. His music is his impact. Like many artists who have huge blockbuster albums, though, it became his downfall. It took Polow leaking "Love In This Club" for him to even release another single. The impact of his previous album helped that song fly to #1 within weeks. But he steered away from his heartthrob image, got married, acted crazy on TRL defending Tameka, sued his biggest fansite for hating on his wife, and the Here I Stand album was a little too mature for his core audience. By 30, he was cooling off.
But is he iconic in the way Britney or Beyonce are?
No. And that's simply because outside of the music, there isn't really anything interesting about Usher. No iconic outfits, no real iconic routines (even though he is a phonemonal dancer) like "Remember The Time", "Thriller", "Vogue", "Rhythm Nation", "Single Ladies", "I'm A Slave 4 U"...... No snake, no metal glove or alter ego, no bodysuit with the ass out....
There's no frenzy. There's no real hype. He can probably walk down the street without causing too much of a commotion. And now he's sitting on The Voice alongside Shakira (who's being paid more). When Mariah did American Idol, she was paid the most. When Britney did X-Factor, she was paid the most. And sadly, that just makes him seem desperate and washed up. Not to mention, he's on Snapchat desperately taking nude pictures. Didn't he just star in a movie? If he were truly ICONIC, everything he does would in someway become an extension of his iconography. He's just regular as hell now.
Usher is an R&B legend. But he is not ICONIC.