I tried to tell you and that other guy before Doc that thankfully this horrible movie franchise is coming to an end with the third film.This is old news.Amy Pascal said it last year that the third film would be the last.It makes since that it would be the last one because Mcguire and Dunst have made it perfectly clear that this will be their last outing as Peter Parker and Mary Jane.They are only signed on for this last film and have no intention of signing on for anymore sequels.So it makes since that sony would want to end it with the third film and not make the same mistake that the Batman movies did which is try and continue it with a different actor.
It does make alot of sence to only have 3.....the actors will be to old to keep going, and it would be suicide to have different actors....But as you all know hollywood can do soem weird things...they can make people look alot younger than they really are..so there may be a chance, but VERY doughtful of there beign 6 movies....