Sean Brady is not actually #1. Shavkat is because he’s the next guy in line for a shot. Sean Brady isn’t well-known yet so they don’t want to book him against a box office bomber like Belal. Anyway, Belal isn’t fighting JDM until May this year, and it’ll be at least 3 months after that when Shavkat fights, and another 3 months until Brady fights. So it will likely be a year before Sean fights for the title, best case scenario. He probably wants to get paid, and maybe it would be nice if he could fight a guy who has headlined a PPV. That will almost certainly clinch that title shot.
Another problem with your reasoning is Usman is still ranked in top 5. Well he’s lost 3 straight, and his most recent win was pushing 4 years ago (a very close fight against Colby). By contrast, Colby’s won since then against Journeyman Judas, who was one of the UFC’s biggest stars at the time. He’s on a 2 fight skid, but one of those losses was a championship fight where he took a solid round from the champ. Leon is also on a 2-fight skid, with the added bonus of nobody gives a fuck about watching him fight. Colby’s a huge star that lots of people like you love to hate. So any way you slice it, Colby’s not nearly as irrelevant as you think.
Should the UFC just book its contenders against each other so they knock each other off? No, that’s retarded. The best thing is to book them against someone ranked who is already famous (Colby). If Sean Brady wins that fight, he instantly becomes a big name, and he makes a fuck ton of money. I don’t know why think that’s such a bad idea.