That's what baffled me about the first one. They wasted a whole hour retelling an origin that didn't need to be retold in the first place only to have the rest of the movie be barely different from the previous entries, making the whole rebooting even more pointless.
I've always said they should've continued the story of the previous trilogy with revealing that Topher Grace was Eddie Brock Jr., who tried to step in the footsteps of his famous father, a fearless, muscular reporter who covers wars from the trenches. The movie would see this man, Eddie Brock Sr., return to NY to avenge his son's death, become the real Venom, and from that they could build up to Carnage in the next movies.
I'd argue that Webb's version of the origin needed to be retold due to the way the story is unfolding with Oscorp and Harry etc but it could've been done in flashbacks rather than devoting a whole act to it but that's neither here nor there at this point.