Sounds like they did not even get to the money stage in negotiations. Dovi had already taken a hefty pay cut, so that was not the prime reason.

Ducati appear to have the old Honda mentality, its the bike not the rider.

The NDA Dovi had with Ducati as run out and so he has given his side of the story.

To cut a long story short, during the Summer of 2019 Dovi had a major falling out with Luigi Dall'Igna, who's basically the guy who runs the Ducati MotoGP effort as personal property. Dovi refused to deny or confirm this but an Italian sports paper reports Dall'Igna tried to have Dovi fired shortly after that episode but was stopped by the Ducati CFO since the financial penalties would have been "crushing", so Dovi and Dall'Igna were kept as separated as possible by the staff who according to Dovi did "a cracking job".
Why the quarrel? Dovi voiced a major concern of all Ducati riders: Dall'Igna continously and personally interfered with bike development, overruling the designers or ordering them to disregard suggestions by the riders. It's an old story, basically what made Stoner's life miserable and what drove Rossi to take a pay cut just to get back to Yamaha as soon as possible.

While Dovi may have embellished the truth a little, he told nothing new. Dall'Igna is a domineering SOB in the mold of Ron Dennis of McLaren fame and needs a strong willed rider (preferably an SOB like himself) to put him back in his place. Dovi, kinda like Stoner, is too gentle and kind for the task and while Rossi had the disposition and leverage... well, he knew Yamaha would take him back in a heartbeat so he just pocketed the cheques and waited for his contract to run out.

Dovi also said he will be back on track February 28... an MX track to be specific. The Italian MX commission has granted him use of #34 for the whole year so he's as pleased as punch for now.

So they (Ducati) took him from Aprilia and with both brands never succeeded?