While other reality competition shows are on the wane in popularity, ratings and relevance, NBC's America's Got Talent is emerging as a clear winner with the conclusion of its 11th season, the show's biggest so far.

With the crowning victory of media sensation Grace VanderWaal and the return of Simon Cowell to American television, the talent show competition enjoyed the highest ratings of the summer, consistently finishing as the No. 1 show with a season average of 13.4 million, its highest numbers since 2011. The season finale pulled in 14 million viewers, topping the previous night's performance show with 13.7 million, with America tuning in the next night to see what all the fuss was about.

And what a season it was. With stellar talent provided by the 12-year old VanderWaal, mysterious psychics the Clairvoyants, powerhouse vocalist Brian Justin Crum, Philadelphia Eagles magician Jon Dorenbos, prop mime Tape Face, and standards crooner Sal Valentinetti, this was one of the show's strongest contestant pools yet.

Watch 'America's Got Talent' Winner Grace VanderWaal's 7 Best Performances

This was also a summer of viral moments. The 82-year old John Hetlinger stunned audiences with his unlikely performance of Drowning Pool's nu-metal hit "Bodies," and later performed live with the band at festival gigs. When stuntman Ryan Stock was accidentally shot with a flaming arrow by his fiancée, AmberLynn, America gasped -- then shared the moment millions of times online. VanderWaal's audition video alone racked up nearly 38 million views on YouTube.

How did America's Got Talent continue to rise in relevance during a year where American Idol went off the air and competition shows seem to generally be fading? Speaking to Billboard, Cowell says several factors came into play.

"I had a feeling when we were filming the show that this was going to be a really good year," Cowell relates. "I think the producers did an outstanding job, and you get great talent on the show, and all these things come together to create that incredible sweet spot, which is what I think we had. It was just a gut feeling that there was still room for them to grow with this format."

That variety, he suggests, filled an entertainment void where "an entire family of all ages can watch it, and they all find someone they can root for. "

The former Idol judge and X Factor creator says judging everyone from magicians to singers to jugglers was fun for him as well.

"You never get bored," he says. "Sometimes, when you’ve got singer after singer, it can get a little bit monotonous depending on who you have that particular season. With this show -- particularly the new edition -- literally, a box can walk on and you’re thinking, “What’s in the box?” I haven’t got a clue who’s auditioning. They never tell us. It reminds you of being a kid again. It’s sort of fun, magical, weird, but all the things I like."

'America's Got Talent' Judges Simon Cowell & Mel B. Talk Going Live, Show's Promising Singers

With that broad an appeal, is it within the realm of possibility that the show could land a coveted Emmy nomination? Cowell is hopeful.

"If I had one wish for the people who worked on my show over the years, it would be that. It’s not for me, it’s for them," he says. "I think they’ve worked so hard and they’ve created something which is really unique. If anybody’s thinking about who to nominate for next year, I would really ask them to consider what these guys have done because they have done an incredible job."

The basic premise of the show, "that anybody can be a star," is still the driving force of America's Got Talent, says NBC reality TV exec Paul Telegdy -- and this year's voting patterns showed that the audience was invested in more than one artist.

"I’ve seen every vote -- this is the closest it has been, ever. It would’ve been a recount if it wasn’t so methodically done by computers and the app and digitally delivered," Telegdy says. "I think people thought that Grace was a runaway victory, but it was the closest I have ever seen in a three- or four-way race in any of these shows – and I’ve seen the numbers on nearly every competition show."

With the addition of Cowell in the chair last occupied by Howard Stern, the show's focus also shifted a bit, to give singers another avenue to compete in a shrinking television field.

"I wanted to prove to singers that this is a viable show for them, and that they can trust the format," Cowell says. "That was really the main objective, apart from making the show as good as possible.

With the discovery of VanderWaal -- the vocal pick of judge Howie Mandel, which Cowell jokes was "quite annoying" -- the British music mogul is off and running with the pre-teen's career. She will be signed to his label, Syco, as well as American label Columbia, and is set to headline three nights in Las Vegas, alongside fellow AGT contestants the Clairvoyants and Tape Face. Another "bigger" announcement is coming in 18 months, Cowell promises.

"Simon is an A&R machine," Telegdy raves. "He’s been doing it for a long time, and has an incredible eye for talent. He’s had an amazing first go around at America’s Got Talent."

That said, Telegdy is quick to note that the success of the season is due to more than the cheeky Brit. The chemistry of all four judges -- Cowell, Mandel, Mel. B., and Heidi Klum -- and host Nick Cannon (who the exec calls "the glue of the show") is a formula for a fun, engaging program that keeps viewers coming back. And according to Telegdy, all four are returning to the fold for the show's upcoming 12th season.

"Everything works," he explains. "All four different points of view [represent] a voice for every [single] part of the show."

Telegdy added that the show's relocation to the Dolby Theatre in Los Angeles was a good move, calling it "an incredible venue... perfectly designed for live shows." Cowell says he loved the Radio City shows as well, and that "the New York audience is amazing," but adds that he always felt AGT was a Hollywood show. "It was what was in my mind when I was working on the development of the format," he says of the season's new setting. "I think it ended up where it should have been."

For now, Cowell is enjoying his return to American reality TV, and can't wait to see what the forthcoming auditions will bring for Season 12, as the show searches for the next victor to be showered with confetti.

"It was a really, really great, fun two days," he says of the show's finale. "It was like the old days."