But why would they keep those weeks? To prevent them from going only-VSN, which they own too? And at what cost? I don't really see the benefit to them in that regard.
They exercise ROFR because they buy points low and sell points high. That is their main criterion - it's all about profit margins. They could be more selective and buy at resorts with low MF/point for example, to lower the Trust points MFs - but they don't really do that. I have resale weeks that, based on enrolled point value, have MF/point of 0.30. Would be great for Trust points owners if MVC actually bought those to put in the Trust to lower MFs for all owners, but they don't do it because it's cheaper for them to buy weeks/points at other places.
They will exercise ROFR wherever is cheapest... If WKORV resale prices were low enough on a cost/point basis they will do it, and otherwise, they won't. They may actually find that $15K for 6200 points is attractive. But they won't find $35K-$40K attractive for the OF weeks with ~8000 points. If anything, this will buoy WKORV/N IV/OV resale prices.