I look at the chart you linked and see significant, precipitous declines where the RIAA either ignored negative feedback or outright attacked customers:
Late '70s - disco was pushed on radio, tv, everywhere, and audiophiles (LP buyers) rejected it (the sale of hissing cassettes stayed flat unti CDs came along)
1990s - CD sales flatten as the loudness war gets really noticeable
2001 - CD sales take a nose-dive after the Napster decision (Feb. 2001)
2005 - CD sales make a tiny comeback, along with digital, then both plummet as the RIAA lawsuit campaign focuses on university students and the MGM v. Grokster decision comes down
Has the RIAA finally won the war against its customers?