I've noticed a more and more used practice from publishers, when it comes to releasing new games. They seem to have a bunch of DLC, put it on the disc, and then charge you for it. For example, the following are available on the PS3 version of Assassin's Creed 3
Captain of the Aquila's Uniform
Traditional Colonial Assassin Outfit
Obwandiyag's War Club
Pirate Flintlock
Boarding Axe
Scottish Flintlock
upgraded Naval Convoy
new colors for the Aquila
Lost Mayan Ruins
Ghost War privateer contracts
Sinking a Secret privateer contracts
Sharpshooter Package
Redcoat Package
Some if not all, of them are used as preorder incentives, and in order for the customer to get all of the above pieces of DLC, you will have to buy the game from several different retailers, over and over again, even though it is on the disc already. Assuming you aren't completely crazy of course, you could just wait until it is available on PSN, XBL, or whatever intrusive DRM such as steam it is using on PC.
Yet, the problem remains that you've already bought and paid for a game, on a disc, but you don't get what is actually on the disc.
What do you guys think of this? Any argumements that can support this practice?