Yamaha's dilemma
You all remember Kevin Windham? Yamaha took him under their wing when he was a mini rider and prepped him to be the next big star. Then, when KW started on 250s, he got into a fight with the team manager and walked out. All the years Yamaha invested in him were lost.
Yamaha can't or won't get into a bidding contest with big red for proven American riders so they are forced to look overseas for talent.