You'll find a lot of people who look down on Gary Gygax, and the game system (D&D) he created - heck, back when I ran a game myself, I not only created a game world, I devised my own magic and combat systems, because I thought the D&D one "sucked". However - I wouldn't have been inspired to do that had D&D not been created first.
This article makes an even bigger point - Gygax was the progenitor of all modern video games:
In creating Dungeons & Dragons, Gygax and co-creator Dave Arneson didn't just build a blueprint for the digital RPGs to come; they built the progenitor of most contemporary video games, irrespective of genre.
because video games - unlike older games - have a story to tell:
Today most gamers take it for granted that games have stories, yet most traditional games -- chess and checkers, tag and hide-and-seek, baseball and basketball -- don't have any story.
We have Gygax to thank for a lot of that. Sure, his magic system had holes, as did his combat system. He was the pioneer though, who paved the roads that other people followed and improved. Anyone who likes the places those roads have taken us owes Gygax some thanks for that.