Because aj can't handle pressure fighters and Hearn knew it. Did you see what Nistor, Ruiz and Dubois did to him ?
My guess is that before Ruiz, Chisora was a little too hard to put away, bad matchup, to make it worth it as Chisora had no belts etc. I think AJ would likely TKO him like Haye but if he didn't manage to early on, might get in trouble. After Ruiz they wanted no part of Chisora as it basically confirmed that AJ could be ground down by a game pressure fighter. We forget sometimes that AJ is the most protected and 'planned' fighter of all time. Every single thing that happened was calculated and minimal risk for reward. This was on full display when they avoided Fury for huge money and belt all to take a low risk path to the Dubious shot who they considered an easier opponent and were confident of beating due to Dubious being vulnerable. It's true he was easier to beat than Fury but in a way more dangerous. That was a bad calculation on their part. But notice they've then ducked the rematch due to the risk and no reward (no belt). Many fighters would want that rematch after the humiliation but they went back to calculating the next move for their dying brand.
Their timelines never matched up. Chisora was considered washed up by the time Joshua made his debut. Joshua was then carefully built up while Chisora himself was doing a rebuilding of his career, which got set back by Pulev. Joshua then beat Whyte and got an easy title fight. During Joshua´s title reign Chisora took several more losses, including two to Joshua´s rival Whyte. Then Chisora again rebuilt only to end up loosing a string of fights to Usyk and Parker. Joshua was supposed to make his US takeover a reality, and for that they looked for the most marketable American they could find, who also was low risk. Good news! Matchroom happened to have been building up Jarell Miller for the last couple of years. But then Joshua ended up fighting Ruiz, and that series took a long ass time. Then Joshua fought his mandatory in Pulev, and next up was another mandatory in Usyk. Chisora ended up loosing badly again to Fury, and many thought his career was done for. He also jumped ship from Matchroom to Queensberry. Would be a good matchup now, and both schedules are open for it. Plus its guaranteed to be a big fight.
During AJ's peak as champion, Chisora was miles and miles away from a title shot - I don't even know if he took boxing seriously. And of course, AJ decided to fight once a year for the rest of his career.
Because early on, it seemed like a pointless fight and a waste of time, now he's high risk as ****, low reward.
They are good friends. AJ refers to Chisora as his big brother. Chisora had earlier said that he would never fight AJ but these days I believe hes hinted he would for the money.
Chisora never wanted it. He can't handle explosive punchers. Haye showed that. Joshua wasn't great but he was a bad match-up for Chisora. And, yes, they were old friends, if that's relevant.
If Joshua had fought Chisora back when he was champ people would have said he was taking an easy pointless fight. Similar to how everyone was criticizing Fury for fighting Chisora. When Joshua was still on the come up the timings never matched. This matchup could still happen though, the IBF is a favourite of Joshua's and Chisora is ranked highly with them.
Cause up until the Dubois fight it would be seen as AJ ducking top competition to fight a bum. Just like Fury vs Chisora III.
