The thing here is if the promoter of Inoue would consider a fight with Casimero. It was Bob Arum's fault that the second chance for both boxer to fight got dissolve. Remember the 1st fight were canceled due to the pandemic and the second possible fight did not materialize because Bob Arum has a different thing in mind. The fight Inoue - Moloney should be Inoue - Casimero but then Bob Arum has another plan and agreed with the Inoue - Moloney.
It is indeed easy for these to boxer to meet in the ring but their promoter made it difficult.
Bob Arum is more on the money side, if there are many readers who can be converted to a possible viewer/ticket sales, maybe Arum will consider this possibility, for now, he still leaning with his cash cow Inoue and he needs to maximize all the profits that he can earned from his champ, still have a chance for Casimero but like what I said above he need to make his way to bring his name up inside the division and force the fans to bring him to an option for Inoue's fight.
I think it's more on Inoue's fault why he didn't get the chance to fight Inoue. All he had to do is make weight and win the fight against Butler. Now, it's getter harder for him to call out Inoue because he has no belt and not even recognized top 5 in any of the body in his new weight class.
So forget about Casimero for now, the focus of Arum is Inoue against the champion in 122 lbs like Fulton and Murodjon Akhmadaliev. That is where the money is right now, not Casimero to be honest.