My theory is that 5DV is going to happen at some point in a smaller series - for those who need every electron from the battery to be spent efficiently out in the field, far away from a charger. But as many have said, it makes sense for Canon to kill off hope for it until they sell enough R5 cameras to cover the development costs and then some.
Just because the R&D for Mk V was stopped doesn't mean all data has been destroyed and all progress has been scrapped. They have so much experience with this series that they could announce it in a month when they want it and have production going in another 3 months (and I think I'm being generous here), they just have to decide on what mix of features to put inside.