It's being demolished in both Hong Kong and Tokyo, and if they were to expand Paris' Tomorrowland in the future, it would likely go away over there as well. I'm sure they have considered the possibility of getting rid of the American versions as well, though with the Honda deal going on in California, we'll have to wait and see.
I personally believe that the Tomorrowland Speedway occupies a lot of space, it's noisy and smelly, and you can find something similar in many local parks around the country. I wouldn't mind if something else was being planned for that space.