Ah... i actually don't understand that why you and sam_p_lay and it's appear sunius separating publishers from developers.
Yes for example on this list, id Software actually makes games. But a company like EA doesn't make games at all. They pay to have games made by members of their publishing house (who are developers similar to id) and they pay to market those games, but they have very little input regarding the creative and technical aspects of game design. The last time EA actually made its own game, some members of this forum weren't even born yet.
Hopefully that clears it up a bit. There are other similar examples on this list, those are just 2.