I don't know if you meant to compare Bagley to any of those guys specifically, but it's probably worth noting that those three #1/#2 big man picks all failed for very different reasons.
Oden failed because his body was fundamentally broken. He was talented, he was strong, he was athletic, and his frame just wasn't able to support how massive of a human being he was and the stresses he put on it as a professional athlete. Bagley simply does not look to have that problem - he's not too muscular for his frame. I know that we're all a bit concerned over Bagley's early injuries, but they are nothing like Oden's. In seven years in the NBA before finally hanging it up, Oden barely notched over 2000 minutes. Bagley will likely pass Oden's career minutes before the end of January. A career completely derailed by injury isn't out of the question, but it doesn't seem likely for Bagley.
Thabeet failed because he fundamentally lacked the athleticism to play at the NBA level. He was slow, and he couldn't move, and he couldn't react to the NBA pace. That made him unplayable. This is clearly not a problem for Bagley, who is at worst a fine NBA athlete and at best an outstanding one. Bagley is no Thabeet. (Bagley will likely pass Thabeet's career NBA minutes by the end of the season.)
Darko failed because he just wasn't very good at basketball. He couldn't score - Bagley's career points per 36 is nearly DOUBLE Darko's. Furthermore, Darko's offense was almost exclusively from within 10 feet of the basket. Darko went 0-6 from three in his NBA career, and was only worth 0.6 points per shot when he attempted one from outside 10 feet (Bagley, in contrast, is 0.83 points per shot from outside 10, and looks to be capable of better). Inside of 10 feet, Darko shot 49.5% - Bagley is at 56.4%, and has not only a better free throw rate but a much better FT%. Bagley outrebounds Darko by 2.6 rebounds per 36, and for all of the "Manna From Heaven" Vlade-Divacesque passing skills that David Kahn saw, Bagley is only behind Darko by 0.3 assists per 36. For all of that, Darko played over 85% of his career minutes in his age-21 season and later - so in his "prime" of skill - while Bagley has clearly outpaced him in his age-19 and age-20 seasons alone with much improvement to expect. Bagley is no Darko, we can already cross that one off the list, too.