From what I remember back in the day (2007-2008) about the rumors behind Spider-Man 4.....
Sony ditched Spider-Man 4 cause Raimi couldn't come to an agreement with Sony over the script treatment. Raimi was already unhappy with the Sony Execs forcing him to include Venom into Spidey 3 as he was always vocal about not being a big Venom fan and didn't want to tackle that story. But he was under contract for 3 movies, as was all the actors.
After the dust settled with the negativity and Spider-Man 3 still making good money, Sony tried to get everyone back on board for a 4th film. They wooed back Raimi telling him he would once again have full control. Tobey Maguire and Kirsten Dunst both agreed to come back for a 4th installment if and only if Raimi was involved as Director and wrote/approved the script. But once again, Sony was pushing ideas on Raimi. One rumor was Raimi wanted the Vulture, but the comic book version IE being an old man. But Sony wanted a young actor and supposedly was trying to force the idea of making the Vulture a woman, a young hot women. Negotiations broke down, no script was ever written, and when Raimi backed away so did Tobey & Kirsten. No Directer, No Actors, No Spider-Man 4.
Sony was then under the gun time wise to get a movie out, so they hired all new people, thus the reboot.... Criticism over Spider-Man 3 had Nothing to do with there not being a Spider-Man 4. Raimi was a huge Spider-Man fan, thus why 1 & 2 were so successful and well liked (still to present day) and felt so true to the original comics brought to life on the big screen. He had complete control over the 1st 2 movies. Sony, thinking it was their genius as to the movies success, crafted ASM, followed by the even worse ASM2 with the wrong people, thus why it sucked so bad.