They went out and became the best international recruiters. They have something like 9 NBA players that they’ve produced from other countries.
There is no evidence that they’ve ever been dirty. They were just smart and creative about looking beyond our borders for recruits.
On top of that Few is a really, really good coach. And he stayed to develop a legacy instead of jumping to a bigger school once he established that he was good.
So then you had a great coach with a history of success and now you can recruit whoever you want because the best players want to be in the Sweet Sixteen or beyond every year and more than almost any other school Gonzaga can promise that.
Additionally, it just doesn’t take as many resources to run a good basketball program. It’s not like football.