U.S. Steel operates integrated mills, which make steel from raw materials. "Mini-mills" make steel using electric arc blast furnaces to recycle existing steel.
If you need very high quality steel, you have to get it from an integrated mill. Everyone else can use the recycled stuff. The real benefit that you are talking about is the fact that recycled steel quality is improving enough to be useful in more applications.
PS - U.S. Steel is converting their Alabama mill to an electric arc blast furnace (they may have finished by now).