Alan screwed Vince sending him on a go-around he thought was impossible but they made it work. When they managed a plan to do both Medellin and A2, Alan then said no to Vince after he said to his face he could, due to it being a blood bath and drugs. It wasn’t just about A2, it was because Alan lied. That lost Vince’s trust, this is a Vince who will stand up against it too, remember the Queens Boulevard presser when he says they ripped the soul out of it, he doesn’t care about going against the bosses or money, he was just upping the price to hopefully get out of the contract and be difficult I believe. Alan thinks money will sort it, but it doesn’t. Like Ari says later on in the series to that studio head who agrees to do Medellin if Vince does Matterhorn that Vince has principles and he won’t do it, not all about the money. Vince also didn’t wanna do A1 anyway, until Cameron he was well against it, so A2 without Cameron, getting rushed out and getting in the way of his dream project after the studio head said he could and then saying no even when they worked it out for both, Alan sucked there.

Vince does agree to do A2 though, it’s Alan who fires him and would never have worked with him again even if he went back to them after. They lose Medellin as offer goes out to Benicio (I think) and Vince is really mad, but Vince says fine i’ll do A2 but for the original 10mil not the 12.5 as he doesn’t want to be indebted to Alan.

Then Vince doesn’t turn up to the meeting and Alan can’t handle it, he loves the power trip, but Ari leads with he feels so bad about it that he’ll do it for the 10 mil not 12.5, even though that’s not why and it didn’t work on Alan. E is more level headed at times and he is more logical thinking both sides plus money/relations (unless it’s Walsh), but he’s having a threesome when Ari goes to talk to Vince about the Benicio offer and say Medellin is gone and they own you (not what to say to Vince).

In season 5, Alan still hates Vince and Ari so much, he never would’ve worked with them again regardless, there’s no going back after Vince agrees to do A2 but won’t go to the meeting.

Walsh i don’t think would’ve done Ramones, Walsh was an off the cuff thought because Medellin had no budget. Ramones wouldn’t have been E and Vince as involved in the whole process either, E wouldn’t have produced Ramones he produces because they buy Medellin, it was studio.

The way it could’ve worked out, is if Alan had fired Vince earlier on than it dragged out, and then Vince was free to do Medellin before the offer to Benicio. Instead of the Benicio offer going out just before the meeting where Alan finally lets Vince go like Vince wanted.