I remember the first game I saw was Zork. My brother was printing out pages and pages on track feed paper. It was alot like ‘Choose Your Own Adventure’ books. I remember sound blaster had a good text parser in ‘Dr Staboto’. I’m not sure on the spelling.
Some of the games I thought were ground breaking were not Sierra’s: Mean Street, Ultima (Avatar), Street Fighter II.
The guy has all the rights to his believes but I don’t see how Zork influenced future games? It was one of the originals and has a great place in history.