What happened to Disney MGM Studios?

I went there way back in 1992 and it was called MGM Studios. Some time after that, all of the sudden it was Hollywood Studios. It is fine that they changed the name of it, but in every single Disney World special I see on television or otherwise, it never mentions what it was originally called. All they say is that they built Hollywood Studios. It is as if they are hiding things and I find it a bit odd.