I agree with several of the things you wrote, but I reckon we must take into account that we will never know a good 70% of what happens in the teams when the doors are closed. I think something happened in Ducati and I think it's not strictly related to money. It's a team fully composed of Italians after all, we are good at being drama queens
From the recent Italian interviews of Ciabatti, Dall'Igna and Dovi (3 extremely chilled lads), it's very obvious that there is a certain tension in the team. There's been tensions also between Dovi and Jorge but that is natural.
Also Marquez in the latest press conference stated that he'd like to have Dovi as a team mate, why on earth would he say that if he didn't know that that is a possible scenario for 2019?