Quite a few of TSR’s successes such as Temple of Elemental Evil and the D&D cartoon are the direct work of Gary.
This is an aside from the main discussion, but T1-4
The Temple of Elemental Evil is a good example of how TSR worked (or did not work) under Gygax, and why there is so much argument decades later about who wrote what and who deserves credit.
EGG himself wrote T1
The Village of Hommlet and TSR published it in 1979 to great acclaim. It is still often held up today as a landmark in old school adventure design. ToEE was originally meant to be published as T2, a direct sequel to T1, followed by T3 and T4, but none of those products ever appeared. Instead Gygax got distracted by other projects, including the D&D cartoon and the attempted movie deal.
In 1982 Gygax developed a 1976 tournament module based on a Rob Kuntz dungeon level into S4
The Lost Caverns of Tsojcanth. That same year he also wrote WG4
The Forgotten Temple of Tharizdun. Lawrence Schick has speculated that Hommlet, Elemental Evil, Tsojcanth, and Tharizdun were all originally supposed to be published as the WG “World of Greyhawk” module series, but EGG wanted to get Tsojcanth and Tharizdun out into the marketplace immediately, so the four linked adventures got published out of order in the S, T, and WG series. Some people today run them as a Greyhawk adventure path, sometimes mixing and matching with the Greyhawk-themed supermodules A1-4
Scourge of the Slave Lords and GDQ1-7
Queen of the Spiders.
When Gygax was forced out of TSR he left his notes for T2 with Frank Mentzer, who completed the work so it could be published in 1985 as T1-4, incorporating the original T1 adventure. My friends and I were just beginning to play D&D around the same time, so ToEE seemed like the ultimate D&D mega-module from the man himself, the one and only Gary Gygax. The iconic Keith Parkinson painting looked like the covers of heavy metal albums by Iron Maiden, Judas Priest, or Metallica, and that only enhanced our interest.
We may have hyped it up too much in our minds though, because once we started playing it unfortunately turned out to be a bit of a slog. Fight a barrack room full of goblin guards, who call for help from the next room full of hobgoblins, who call for help from the next room full of bugbears, lather rinse repeat. I cannot remember if we ever actually finished it. I have seen complaints online about how the elemental nodes on the lowest levels were basically left unfinished for any DM who felt like stocking them.
The moral of the story, if there is one, is that many of the big ticket items from the dawn of the game were not actually heartbreaking works of staggering genius, but team efforts subject to the priorities of running a medium sized business and various personality conflicts. I think we would do well to try to remember that everyone in the history of the hobby was human, with all that entails.