The 25-year-old South African 400 metres world record holder just missed out on emulating Johnson's feat of the 200/400m world championship double, which the American achieved in the 1995 championships, when he took silver in the 200 metres on Thursday behind surprise victor Ramil Guliyev of Turkey.
Guliyev took the world title in 20.09sec from van Niekerk (20.11), with Trinidad and Tobago's Jereem Richards third (20.11).
However, Olympic 400m hurdles champion Dalilah Muhammad was unable to add the world gold as she was run out of first by compatriot Kori Carter, the 25-year-old previously regarded as a journeywoman.
He finished sixth in the final.
"Maybe at the next competition, everyone will look at me instead".
Richards, a World Indoor bronze medallist in 2012, recorded the best result of his career as he was third.
It would have been a tough quiz question before August 10 to name the second-fastest junior ever, but it was Guliyev, who posted 20.04 as a 19-year-old when representing Azerbaijan.
"It was a tough week", said Van Niekerk, who was in tears during his interview with BBC Sport.
"I delivered my best race at the right time".
He said: "It's one of the craziest championships".
"I will leave the championships with my heart broken". There are many people who don't think I deserve this. I think it's great for my career and another moment to be grateful for.
"I work just as hard as every other competitor".
Claye, 26, had changed lead with Taylor in the first three rounds in the final but the Rio and London Olympic runner-up had to settle for the silver in 17.63. "Me and my coach (Bobby Kersee), our whole goal and focus was to get on the podium this year, it's what we've been committed to".
But he was pushed all the way by Claye in a fine competition, the latter jumping 17.54m in the first round before Taylor passed him with 17.57 in the second round.
But Dina Asher-Smith is into Friday's 200m final after running a season's best of 22.73 to finish second behind Ivorian Marie-Josee Ta Lou in her semi-final, Dafne Schippers of the Netherlands and Bahamian Shaunae Miller-Uibo looking risky as they dominated their semis.
Guliyev, who became a Turkish citizen in 2011 and was cleared to represent his new country in 2013, did fire out a warning in the semi-finals when he won his heat ahead of Webb and Van Niekerk and, though he slipped into the final pretty much under the radar, he had been confident all along.
"I was competing against some of the best athletes in the world, so it didn't bother me that the attention was on them", he said.
"I'm running with anger, 400m is my race".
Katarina Johnson-Thompson remains in the hunt for a high jump medal to make up for the disappointment of missing out in the heptathlon after both she and Morgan Lake made it through their qualifying pools with clearances at 1.92m.