They didn't reboot because they wanted to, Sony was going to continue the series, but when they totally took away Raimi's job in the third one he jumped ship, and then main characters followed. This is a reboot because they had every intention to continue the series, but simply couldn't because they lost the vital cast and crew members. It's the same studio, they just forced their own hand when they decided to sabotage Raimi. It's like when the Jazz traded Deron and decided to rebuild sooner than they initially intended because they knew that they were going to lose the face. They simply decided to move forward as a franchise by starting from the ground up with new parts, not just to make an extra buck.