EA (I'm assuming other publishers also) have a programming team that they have available that they use to help all studios. They also frequently shuffle people from one project to another as projects get finished. I'm assuming tech is shared whenever possible.
Thing is, art is going to be a large cost and except for mundane items not much of that can be shared. Licensing fees (all those sports and movie games) can't be shared. And the larger your company the larger your day to day operating costs (building, utility, administration, accounting, etc...). Those day to day costs rise in a non-linear fashion. The larger your company the larger the percentage of day to day costs.
Title could be made cheaper at independant developers (avoiding publishing deals) I think, just due to the massive reduction in overhead. Unfortunately, there's no way for an independant developer to not only raise funds for anything but a small title but then distribute it themselves.
Regards,
SB