But what these few days have shown is the evolving attractiveness of the sport ensures it remains as relevant and captivating as ever, yet cannot sit still.

Athletics is not without its challenges, like every sport, but it is toeing the tightrope between being an entertainment business and ensuring the levels of sporting prowess are unrelenting. Folk feared for the sport following Bolt's retirement; he had transcended it. But here we had new heroes.

Christian Coleman took a giant leap forward as the face of men's sprinting, Kendra Harrison is as impressive and formidable as ever but there are others bubbling along nicely who have the ability to step up and fill the Bolt-less void.

For instance: U.S. pole vaulter Sandi Morris' mother finds out the latest on her daughter's injuries by keeping tabs on her social media channels. After winning the gold medal in her event Saturday, Morris posted a video on her Twitter account, hamstring being iced, eating a burger.

The personable American athlete is exactly what the sport needs to bring in new audiences and retain its interest among the younger generation. Staying attractive and bringing in fresh fans in an ever-competitive marketplace is what IAAF president Lord Coe last year said was a big challenge facing the sport.

Now, as he reflected on a captivating few days in Birmingham, he feels they have taken strides forward.

"The biggest challenge our sport has is how you remain relevant and exciting in the lives of young people when there are so many other competing influences," Lord Coe told ESPN. "We have to understand we are a branch of entertainment, we are proudly fierce and protective of the sport but we have to understand that engaging with young people is very important. The numbers coming through show we are beginning to make inroads in that."

This was a field without South African Wayne van Niekerk, someone intertwined intrinsically in the sport's tapestry after he exploded into its consciousness at the Rio Games with a breathtaking world record in the 400m. Then there were the likes of Caster Semenya, Justin Gatlin and the wonderful heptathlete Nafi Thiam absent. So, too, the bulk of the Jamaican sprinting contingent.

But under the lights, spectators were greeted with an abundance of sporting diversity. Lord Coe said Thursday diversity "isn't something that's nice to have, it's essential". In total there were 140 different federations competing, with an evenly balanced gender representation. He talked of how they were role models in "sport, in ambition, determination, health and fitness".

There are inspirational athletes aplenty. Take Australia's Sally Pearson, who coached herself back from injury. Then there is British middle distance runner Laura Muir, who paid a £1,500 taxi fare to ensure she made it to the arena Thursday to win bronze in the women's 3,000. Then there was Katarina Johnson-Thompson's gold-medal triumph in front of her home crowd in the pentathlon; those budding athletes sat in the stands could not help but wonder if one day, they could be stood atop the podium. New Zealand's Tomas Walsh also won hearts and minds with his championship-record throw in the men's shot put.

Then there was the captivating men's long jump competition, where just four centimetres separated first from third. They were the rock stars of these championships, feeding off each other's energy and the crowd. They need to be given added prominence heading forward: get spotlights on them, put them in the middle of the arena, let the crowd enjoy. The new high jump format where women and men competed in parallel as the sole sport in the arena was also an improvement.

"It's been a fantastic championships," Lord Coe said. "The performances have been sublime starting with the new format around the high jump and there are lots of people who are here for the first time, who realised the absolute theatre that long jump at its very best can be. We saw some head-to-heads on the track - Christian Coleman and [Chinese sprinter] Su Bingtian, these are the great names coming through so there's a lot to take from these championships."

There are challenges, too. The awkward Russian question continues to hover over the sport, as it did the Winter Olympics. While the International Olympic Committee has decided to reinstate Russia just a matter of days after Pyeongchang 2018 ended, the IAAF had them competing here under the "Authorised Neutral Athlete" banner, as they had done in the outdoor World Championships in London last summer.

Tianna Bartoletta was awarded a gold medal here, 12 years after she was beaten to the top of the women's long jump podium by Russian Tatyana Kotova only for her to then have the medal stripped due to doping violations. Bartoleta's response on social media shows bad blood remains.

For those competing under the ANA banner, they opened the competition with double gold in the men's and women's high jump, the first two events of the championships, with Mariya Lasitskene later lamenting those who were absent and conditions she believes to be "unpleasant" concerning not being able to wear her nation's colours.

"It's important that, until we are entirely satisfied the federation has met the objectives we have set and agreed with them, then this is not an unreasonable interim position to have," Coe said, while waiting on the report of the IAAF's taskforce for their views on Russia's reforms programme.

Confusion also reigned over the long list of disqualifications for lane violations, including one heat of the men's 400 where all five athletes were penalised. It was unchartered territory, continuing into Sunday's session with the Jamaican women's 4x400 team disqualified for a violation in the changeover to join Spain's Oscar Husillos -- who came first in the men's 400 only to then be disqualified -- in venting their fury at what they deemed sporting injustice.

But this was a competition dominated by the USA. They finished with six gold medals, comfortably ahead of the chasing pack -- only Ethiopia and Great Britain won more than one. They brought their stars, while some nations involved in the Commonwealth Games later this month opted not to.

The capacity crowd on Sunday, and those who made it on Friday as Storm Emma froze Britain to a standstill, shows there is still an appetite for the sport. There can be no complacency, it needs to be an ever-moving narrative. But in the likes of Coleman, Morris, Luvo Manyonga, Harrison -- and from a British perspective Johnson-Thompson -- the sport looks to be taking the right strides forward in a new chapter.