The problem, I think, is that publishers see too much money to be made from DLC. Pretty much every new release has post-release (or sneaky on-disc) DLC these days, and with Call of Duty map packs selling millions, despite the questionable price point, you can see why publishers are tempted to offer DLC for their games.
It's just a shame. It's a shame that a once great idea has been corrupted by greedy minds, hungry for every penny they can squeeze out of gamers. These dirty tactics need to cease. Now. If any publishers are reading this: believe me - more gamers will be willing to buy your DLC if you actually make new content worth paying for, sell it at a reasonable price and don't rip it out of the main game just to sell it back to me.
"Jake," you might say, "you don't have to pay for DLC if you don't want to. Just don't buy it." Well, yeah I could just not buy it, but the point is, often times I shouldn't have to.
Oh yeah, I almost forgot... horse armour.