I don't think he's fallen at all. Despite what some may think about the quality of the Amazing Spider-Man movie, it was successful. In fact, it was more successful than any of the other Marvel movies you mentioned in worldwide box office receipts.
Amazing Spider-Man: $696 million worldwide
Iron Man: $585 million
Thor: $449 million
Captain America: $368 million
The problem is that it looks pale in comparison to The Avengers, which combined all those other heroes into one massive team-up movie, and made billions. Not really a fair comparison.
and as far as comics, Amazing Spider-Man by Slott has been consistently Marvel's #1 (non-event, non-team book) seller through Diamond.
not to mention there is still way more merchandise of Spider-Man than anyone else from Marvel.
"I'm sending him a bouquet of cans."