The Legend—the man who wrote the in-universe comic book stores that basically functioned as Supes propaganda—teaches Hugie about the history of The Seven in The Boys #22 by Garth Ennis, Darick Robertson, Simon Bowland, and Tony Avina. He discloses that Victory Comics, the universe’s Marvel Comics, ceased publishing all of their comics following the aircraft disaster and changed, rewrote, and scrapped tales to avoid using the term “war.” As a result, The Seven were compelled to remain hidden from the public. A deliberate attempt was made to avoid giving the heroes an aggressive appearance. Thus, instead of having an overarching enemy like Thanos, The Seven’s adaptation of the Infinity Saga became “The Infinity Debate.”

It makes sense why they never had a parody of the antagonist Thanos, given that the Infinity Saga in The Boys reality evolved into the Infinity Debate. In-universe comics were altered to reflect Victory Comics’ desire to keep the terrible episode involving The Seven under wraps, perhaps negating any mention of Thanos in the books.

Having said that, this does not exclude the possibility that The Boys’ reality contains a version of Thanos. However, the Infinity Debate took a much lighter tone than the Marvel Infinity War books in the in-universe comics showcasing the most amazing (and made-up) deeds of The Seven, since they sought to represent the Supes in a non-deadly manner, which meant no satire of the evil Thanos.