I am in the same boat as you. I looked at this and thought about buying it but, I don't need it so I didn't. I could be convinced otherwise but I would rather buy more sourcebooks that I may or may not read/use.
It's a little sus that it's published by the same company that owns Traveller now. That said, I think $7 is not a lot of money for a book you're interested in. $60 for the physical is outrageous though.
Definitely NOT outrageous. $20 in 1982 is equivalent to $66 now. SOURCE. (The purchasing power of the US dollar is a third of what it was in 1982.) I have a copy of the book on my desk and it is incredibly well researched and printd and bound on good quality paper with excellent art in four colors. Look at Shannon's other work on RPG history and you will see some fantastic work.
I don't know where this 1982 reference point is coming from. This is a history book about a game series, not a reprint of an 80s game. If you walk into a book store and pick a history book off a shelf, even a well researched, nice, hardcover, it's like $20-25.