A decade ago, Apple Inc helped revitalize a music industry hit hard by online piracy with its iTunes Store. Now, amid a steady slump in digital downloads, the industry is hopeful that the tech giant’s new streaming service will give record companies another desperately needed boost. Apple Music, unveiled Monday and scheduled to launch at the end of the month, will offer subscribers access to a vast library of songs for $10 a month, but has no free on-demand tier unlike industry leader Spotify and others.