Automatic Sheet Music Turner

Watching my son's concert last night I was surprised that the musicians still had to turn their sheets of music by hand. Especially the pianists, causing a brief stoppage of music. I asked my wife, "Why isn't there an app for that?" This morning I saw that someone had invented a battery operated page turner but that seemed a little primitive. So I searched and found this App that almost does what I pictured.

 While my idea had it scroll at a certain speed given the song's tempo, this app listens to you play and keeps track with when you need to turn the page. It follows along, even as you change tempo, make mistakes and pause. It can distinguish your playing above background noise and even other people playing music in the background.

The only problem is that the app still moves one page at a time. Can't someone create an app that scrolls down the lines so you always see the line you are working on, one above and two below? Or is everyone so used to pages of music that they cannot adjust to a scroll?