TOM, your view of Stan and Marvel is about as facile and simplistic as you believe Stan's work was.
Much has been written about Stan's contributions to culture, and to the shaping of kids' curiosity, worldview and self-confidence in the 1960s and 1970s.
He created a world populated with outsiders and loners who struggled against both external forces (fascism, bigotry...) and internal (grief, self-doubt, addiction...). It was powerful stuff for adolescents, teens and young adults in the 60s. Stan's dialogue was jokey and silly, but the stories were often profound, especially for a 10 year old.
Stan handed the reins over to other writers in the late 60s - people like Roy Thomas and Steve Gerber who expanded on the concepts and mandate that Stan created. When I was 11 years old in 1968, it was in a Marvel comic, The Avengers #57, that I was first exposed to the works of Shelley, when Roy Thomas quoted "Ozymandias" in a scene about the death of Ultron. I've attached that page here. The impact of that single page has stayed with me for 50 years.
And I've also attached an example of Stan's Soapbox, the editorial he wrote that appeared in every Marvel comic. Again, for a kid in his teens, this was powerful stuff.
So yes, on their surface, Marvel comics and the Marvel movie universe may seem shallow, yes, the movies may seem to be bombastic and repetitive, and the Marvel universe may appear to have swallowed the movie industry whole. But there is more to Marvel and Stan Lee than you are willing to give credit, and if Marvel movies aren't your thing (personally, honestly, I don't much care for them, but they aren't being made with me in mind), there are still many "adult" films being made. Most of them are now being made for cable, though.
