I agree with the OP, but it might be in part because I have slightly OCD/completionist tendencies. And also that I really want to be able to play as the BTAS and DKR versions of Batman and don't particularly want to buy two copies of the game from seperate retailers in order to do so, so I am slightly vexed.
I also have issues with this because, well, I love old games. And I love buying old consoles off eBay and playing old games. And I realise that the new games of today are the old games of the future.
Why is this relevant? Because 10 years from now someone is gonna buy an old 360 and a used copy of Arkham City off eBay. And they're gonna try to play the game and realise that a big chuck of the content (I'm thinking the Catwoman levels here) is locked behind a dlc pay-wall that is no-longer maintained, and that content will be lost.
And this will be the death of games.
I'm not even kidding. This may seem a valid and understandable business model now, but in the long term it only reinforces the idea that games are disposable, transient and lacking in worth. The trend is to decrease backward compatibility (see the new Wii U) and any attempts at archival are squashed by companies wanting to push their new product and scared of competition from the old one (Goldeneye 077 [the good one] is not resurfacing any time soon).
With publishers deliberately suppressing old games, and sabotaging new ones for further generations, the value of games as entertainment or artistic expression is reduced, and this will unfortunately lead to games never becoming the transcendent medium it so obviously could be.
People still pick up and enjoy old classic books a hundred years later. In a hundred years will anyone pick up and enjoy Arkham City? No. Because you won't be able to play as fucking Catwoman.