backblaze (who uses desktop hdds) says they paid $0.044/gb in sept 2011: https://www.backblaze.com/blog/farming-hard-drives-2-years-a...
Today on newegg it's about $0.03/gb.
Today on newegg it's about $0.03/gb.
I only point this out because I assume you misunderstood what was said about the trend line, if you had another purpose for pointing this out which I am missing I would be interested in knowing it.
I'm not able to find an up to date enough trendline to agree or disagree with his statement.