There could be a chance we here a few of these songs, completed, rather soon and have to wait a few years for the rest.
All Because of You and Electrical Storm came from the same session, two years apart on the releases though.
With the digital age and the succes of Itunes, and with U2's relationship with Apple, it could merely be one song, one digital download, one video, just enough to make the last several shows more interesting. Electrical Storm had a 'vehicle' to be delivered on, these days, you don't really need anything other than a digital recording.