Raimi was fully on board with making Spider-Man 4, probably because he likes his crew and cast and the character and, well, it's work. SM4 would have paid better than Drag Me To Hell, I'm sure.
He quit because by January 2010, he was still having problems with the script but Sony wanted to make the May 6, 2011 date at all costs. Have they really ended up much better with ASM? With how things turned out they could have given Raimi a whole 'nother year, but they didn't want to budge a couple months.
I feel they're blowing their wad by rebooting so early though. And what happens after this reboot is done? Reboot it again? Diminishing returns are going to hit this franchise fast and hard especially if ASM2 blows like it most likely will. I mean, the franchise got so huge because SM1 was sort of groundbreaking and SM2 was legitimately a good movie. With SM3, ASM, and ASM2, you've got a whole lot of bad/so-so movies all in a row destroying the good will the franchise had built up. I only foresee the franchise going down in flames with Sony's current treatment of it, in a way not unlike what happened to Batman in the 90's.
In conclusion, I'm still bitter Raimi was booted off SM4 for some reason. I legitimately cared about the characters in his movies, whereas I only feel a fraction of that for the new characters (as good as Garfield and Stone are.) I was interested in Raimi redeeming himself and his series and seeing what happened next with the characters.
Will ASM2 have an Aunt May "I believe there's a hero in all of us" moment? Will that ever happen again, for that matter? I'm doubtful.