"We set out to do this show and take away as many rules as possible, partly to prove the point that you can sell records and be popular beyond the age of 29," Cowell said after the show's finale Thursday when Stevens, a married father of two, walked away with a $5 million recording deal.
"At my record label we don't have a sign on the door saying, 'If you're over 30 you can't sign here,' " he continued. "We don't run the business that way. This proves that there is a market for older people. I mean, look at Susan Boyle. I sold 30 million albums with Susan. So there's a market out there."
As for Simon's kind words, Stevens told PEOPLE, "[At the wrap party] Simon said some nice things which means a lot; he's the boss – and he seems to have a lot of confidence and in me going forward in my career."
But he still couldn't shake his nerves when it came to that daunting moment leading up to his victory on Thursday night.
"I just remember looking at [my mentor] L.A. Reid, and I said, 'They called my name. I won.' And I turned into a big old puddle of mush and we had a big man hug for a while," Stevens said backstage. "I'm blessed and I can't thank people enough for everything they've done."
Stevens, a road worker from Belton, Mo., who heads to Nashville soon, said he hasn't started working his new record yet, but he knows exactly what he wants it to be: fun.
"I love having fun, so I want that to come through on my record," he says, adding that he will also include some "tug-at-your-heart country ballads."
Reid, who is leaving the show after this season, said he was proud of Stevens and also proud being a part of something much bigger than fame and money.
"The beauty of X Factor is that ... I know we actually get to change some people's lives," Reid said. "I don't really need fame; I don't need popularity. What I really need is that really good, complete feeling that I've helped change someone's life."