I'd have to disagree with that. Even given the countless responsibilities and burdens Peter faced in the early Lee/Ditko days, the Spider-Man comics always had a sense of fun and escapism to them. I think that's the big reason why Spider-Man is as popular as he is today. Spider-Man had a Saturday morning cartoon vibe before Saturday morning cartoons were even popular. Heck, even in dark moments such as Gwen Stacy's death and Harry's drug use, Spider-Man was still one of the lighter titles.