One of the issues with including the liner notes with a digital release is that the copyright for the liner notes is not always/necessarily covered by the same copyright owners as the actual music and the cover art. So including the liner notes would mean a separate copyright issues and royalty. In that respect I can understand why liner notes aren't always (or rarely) included. At the same time, I really wish the liner notes were included as standard and expected with a digital release. Apple tried standardizing (in the Apple sort of standardizing way) a way of releasing digital albums along with liner notes and other interactive extras called iTunes LP. Some albums were released in the iTunes LP format with additional content but in March of 2018 Apple killed that format. RIP iTunes LP 2009 - 2018. It was an attempt. I never bought or tried any iTunes LP releases because I don't do iTunes or lossy. iTunes LP was a revolution that completely missed me.