One of the museums is moving up to the Arts district (Natural History). And it would make a lot of sense to move the aquarium down to the zoo. But I can’t see the fair moving unless some developer has his eye on the property. But let’s face it - if you want land in the area for development, there is plenty available.
They have done a pretty good job of starting to clean up between the fair and downtown. It is even reasonably safe to make the drive during daylight hours.
I drive through there at least 4-5 times a month when I need to go to BaylorDallas. It’s not bad on the North side, but the South side is still pretty bad. The rumored move is it moving to Arlington somewhere around the Palace of Jerry.