What factors propelled Digital Games from $50M to $50B market in 30 years?

I am doing market research on the video gaming industry and like inputs on what (if any) inflection points there were that helped propel the industry from a mere $50 Million in 1980 to $50 Billion worldwide phenomenon in 2012.<p>I am curious how Gaming overcame the primary entertainment channels of the times i.e. TV and Cinema.<p>Is it a combination of great games, supporting paraphernalia (books, merchandise and movies), game evangelists, trade shows etc.<p>Or is it just great games and everything else fell in place?