The problem is developers no longer see the disk going gold as the 'lets unwind and celebrate', instead its more a case of 'we now have 4-6 weeks to do as much additional work as possible, which we'll push in a day 1 update' This didnt happen before the xbox 360 and ps3 because almost all consoles were offline and xbox live on the original xbox was at a time where a large portion of its users had relatively slow net.
People having broadband and consoles being guaranteed a hard drive, and the ability to patch, is what gives developers this get out of jail free card when it comes to adding 1-2 months of development time to the production and release of a game.
Also, currently, PS4 patching system allows difference patching and archive replacement, Xbox Ones current patching system only allows entire files to be replaced.
