Listen, Aspinall and JJ are basically even in the odds... It's a slight advantage to Tom Aspinall... And many experts say this slight advantage is due to Aspinall having a lot of footage of Jon Jones while Jon Jones has no footage of him, beyond flash KOs. So I'm spite of that and Aspinall being younger, the best are basically even... Which shows that even as of now at 37, Jon Jones is still as good as Aspinall.
Now, Aspinall knows that's the huge chance of him getting the best payment he may ever have and although he's also almost 50/50 to lose, the stakes would be way lesser for him, because he doesn't have the legacy and isn't already so financially secure as JJ is. In fact, Tom boy said once that he doesn't blame JJ, because if he were in JJ's position, he would also likely act the same way JJ is acting and would try to avoid the fight. So Aspinall admitted it openly.
But still, Aspinall is smart because he knows that even though he in the same position as JJ wouldn't want the fight, he knows that JJ has a obsessive competitive and a huge ego that is bigger than his own, so he knew that it wouldn't sit well with JJ the fact that ppl would call him a duck... So he knows that JJ wouldn't do what most would, or at least he would, not take the fight, because deep down he knows JJ wants to prove beyond doubts he is the better, so that's why he smartly provokes JJ always saying the word better, because he knows that trigger his competitive side due to his insane competitive nature even though he knows it'd be perfectly understandable to retire after the fight... But he explores this huge competitive and insane high will of JJ to shut up beyond any doubts that he is the best --- which is likely bigger than anyone else's in the UFC barring maybe Alex Pereira --- and so he understands JJ's mentality and also, understands how the fans would bug JJ so much because he has a lot of ppl wanting to see him losing.