I really don't see them creating a physical D&D museum, a place you could go visit in person. That would be cool, but very unlikely to happen.
A museum focused on just D+D is a bit of a pipe dream, but Hasbro has started doing some work with museums: Hasbro exhibit coming to Springfield Museum of History pays tribute to Milton Bradley | masslive.com
It looks like they're just doing stuff with the Milton Bradley lines so far, which makes sense because its probably the oldest active product line they have. But I think it would be possible for them to expand the exhibit into some of the history of their other brand lines. I doubt they'll get to the point of owning their own complete museum any time soon, but small projects like this or traveling exhibits could be feasible.