Simple as it is, Casimero needs to climb rank to be a contender and be recognized.

For now, why the hell Inoue should fight or even start a negotiation with Casimero? Building legacy is associated with the business. Especially if Inoue will won this match against Fulton, Casimero really needs to wait for a long as honestly, Casimero's camp even has difficulties settling a fight against top rank as no bearing if they will fight Quadro Alas for now e.g when their attempt to settle a deal with Luis Nery before failed, etc.

Regardless of Casimero's age, it will only be confirmed if Inoue's camp is ducking Casimero if the latter already established and achieved being a top contender but still didn't get the chance of fighting Inoue. But more importantly, that's not what matters for now. There are lots of "what if" that can happen while Casimero is waiting for his chance to fight Inoue.