It actually shouldn't be as hard as it seems to have been.
Getting a GP ride in 2002 for an American is about as do-able as getting a ride on a non-Soviet owned space shuttle. Especially where Honda is concerned. There has not been an American factory Honda GP rider since 1989--the season Erv Kanemoto and Eddie Lawson collaborated on the 500 championship. (Read a 1990 interview with Erv Kanemoto here)
Hayden has all of the credentials necessary to obtain that ride, at least in a perfect world. He's young, fast, wins championships and has no ugly habits. At 21 he has ten solid years of racing in front of him, preferably on a larger stage at some point.
Insiders say that Honda was unwilling to vault Hayden to the series he pined for, even after he won the US Superbike title. A week after the VIR round when Hayden clinched the title, sources close to Hayden stated that his options for 2003 were to stay in America and race for the Honda Superbike team again, or to race the newly competitive Yamaha M1 GP bike in place of departing Max Biaggi. And Hayden was well-known to not be pleased with racing in America for another season.
So, he signed with Yamaha, or came very close to signing with Yamaha. A story with attributable details and including on-the-record sources of that situation will probably never break cover, but Yamaha, at one point, (only two weeks ago) was making plans with Hayden's name on them. He was going to be Yamaha's, and they almost announced it at Estoril.
At this point it may be important to note that Yamaha and Honda have been bitter rivals for almost fifty years. They have been racing against each other in Grand Prix for over forty years (starting in the 125 class). There probably will never be a collaborative agreement between Yamaha and Honda, like there is between Suzuki and Kawasaki, because if you've hated someone for fifty years it's pretty difficult to stop.
At the last moment, Honda came back with an offer for Hayden that surpassed the Yamaha offer.
In an amazing turn of events, American Honda pressured HRC to step up to the plate and give Hayden what Yamaha was offering him: a seat on the factory GP team. It's not like this was a favor for a rider not worthy, Hayden is probably more worthy than many riders who currently ride for Honda in GP, it's just that in today's political GP climate, getting an American there in place of a Japanese rider takes a Herculean effort.
And that's what happened.