I’m as surprised as anyone that there’s a Spidey reboot immediately after Spiderman 3. Some Sony exec probably hated all those subtle multiple American flags on almost every scene in Spiderman 2 and 3. Garfield, the new Spidey has such a thick British accent that one has to question how he’s supposed to rid of it, and how he actually got the role.
As I understand it, Marvel wanted to end it's association with Sony, but they couldn't do that and keep the continuity of the first three films. By doing a reboot they can have full control.