Not because he shirked training sessions as the Olympics approached (because he did not). And not because he went Bode Miller circa 2006 on the Olympic Village, leaving a trail of drunken photographs for TMZ to follow (because he did not).
Rather, because this is the world he created in Beijing.
Before Beijing began – before Phelps's eight gold medals – American backstroker and world-record holder Aaron Peirsol said his goal was to win three golds. "Usually, three would be very good," he smiled.
And the Ryan Lochtes of the world know it.
Why did Lochte go out after Beijing and start flipping 850-pound tires down a Florida road? Why did he drag around 535-pound boat chains and toss beer kegs over his head?
Because of Michael Phelps.
Granted, this world does not have too many Ryan Lochtes. "A Michael Phelps only comes along once in a generation. But now we have a Michael Phelps and a Ryan Lochte in the same generation – it's a phenomenon you don't normally see," says Glenn Mills, an Olympic swimmer in 1980 who now runs Go Swim!, helping swimmers hone their technique through video training.
But to Mills, London marks the rise of a new breed of swimmers in the image of Phelps and Lochte – swimmers who are bound less by skill and more by how many races it is physically possible to swim during a one-week period. Phelps, for example, could have competed in the 200-meter freestyle in London, but declined.
"It's about being able to make the Olympic team in any way they want to," he says. "Really, it's about the scheduling that limits them more than the talent."
London suggests that "we can expect more of these athletes to come along," he adds.
In Saturday's race (2:30 p.m. Eastern time) – which is longer and more taxing than the 200-meter IM – Lochte thinks his training will be the difference between gold and silver. He already has another apparent advantage: Phelps came out slowly in heats Saturday morning and will be racing out of Lane 8, the worst lane, many swimmers say.
Then again, maybe this is just one of the new "challenges" that Phelps said he was setting out for himself before these Games. Swimming aficionados have learned one thing in the past two Olympics: never, ever count out Phelps.
"He hates to lose," says John Lohn, senior writer for Swimming World magazine.
That mentality is certainly not unique to Phelps. Yet the drive it has imparted might be.
"I don't think anyone in the sport is anywhere near as talented," says Lohn, "and his mental approach is a talent."
Ahead of the Athens Olympics, Phelps trained every day for six years. In explaining this at a recent press conference, Phelps's coach, Bob Bowman, paused to make sure the point came across: every day for six years.
"He worked as hard as he could possibly work," he said.
In other words, he raised the bar. And now Lochte is trying to raise it farther.
"When Michael did what he did, Ryan realized, 'This is what I need to do to get noticed,' " says Mills.
As a result, Lochte was the unquestioned best swimmer in the world in 2011, winning five gold medals at the world championships and becoming the first swimmer to break a world record since swimming authorities outlawed the use of body suits in 2010.
Lochte comes to London as "a specimen," says Lohn. "He put in an amazing amount of work since 2008 to get into this shape."
And Phelps noticed.
"After 2008, I just didn't want to put in the work," he said at a media event in May. "There were times I didn't come to practice. It didn't excite me."
Then, 2011 came, and Phelps found himself losing to Lochte, consistently. The tables had turned.
"Last year, it really got to me," he said.
And that is why the swimming world enters London agape. Phelps went back to work. He topped Lochte in three of four races at the Olympic trials, and now the two of them – according to some, the two of the greatest swimmers of all time – enter the biggest meet on the swimming calendar at the peak of their powers.
In many respects, they come to London from opposite directions. While Phelps is clearly signaling the end of his career after these Games, Lochte sounds like he's only getting started. Rio? Absolutely, he says. Beyond? Maybe.
It is here that the two most magnetic men of the US men's team appear polar. They are friends, they say, but in the pool Phelps is the consummate technician, almost wistfully enjoying his last days in the craft, while Lochte, ever exuberant, is eager to stay in the pool as long as his limbs will allow.
In short, he's still having a ball. "As far as I'm concerned, I'm back to when I was 11 years old and shooting hoops before I go swimming," he said at a press conference.
To Mills, it's almost unfortunate that Phelps and Lochte had to come along at the same moment. "It's a shame they cancel each other out," he says. If Lochte had come to prominence eight years from now, "It would be a different story."
Then again, that makes Saturday night's final of the 400 IM more special. "In a way, it elevates it," Mills says.
Not that tonight needs any more hype.