I'm case you don't know what "Skyblivion" is the I will enlighten you. It is a mod that take the everything about Oblivion and putting Skyrim's graphics on top of it. It's a movement that is going along quite nicely. But what will happen when the mod is released.
  What will most likely happen is that the mod will have a huge amount of downloads. Soon, it will be so big that Bethesda themselves will get involved. They may or may not try to buy the mod and resell the mod as a game. Since a mod of a game is property to the game developers. Plus, Bethesda has done something like this. For example, the robot DLC for Fallout 4 was originally a mod for the most part.
  Another scenario may be that the mod developers will be sued by Bethesda. They are notorious for this kind of behavior. They have sued people for just having the word "fallout" in the title of a game. It's not unlikely. But, I don't see it getting this serious.
  In a way. The mod will be successful. But, it will have a lot of speed bumps to go through. I have a feeling such a project won't be free. With all things gaming though, only time can tell.