Why to have DLC's

[Ancient Seraph]

Is this post to encourage the developers to make more DLC? 1 huge advantage of FS is that it's on the PC. This means anybody can make any addons and it will be compatible. They can distribute it over the internet with no restrictions. On the XBOX however, every single thing has to be checked by MS. Moreover, FS has no competitive element (apart from racing), which means that there doesn't have to be any checks on game balancing. Another reason why 3rd parties can develop addons. In IL2 however, everything has to be balanced in order to keep the game fair. This means any 3rd party addon would have to be checked by the devs and probably tested as well. All this is way too much hassle to actually benefit anyone, except maybe the players.
As for addon scenery, FS is played to experience the joy of flying. This doesn't just include the flying and the plane itself, but can be greatly improved by adding nice scenery etc. The succes of the sales of these scenery addons is directly dependent on the succes of FS itself, most likely not the other way around. If FS wasn't this popular, there wouldn't be a market to sell the addons. This is - sadly - the case with IL2. Moreover, the scenery in IL2 already is quite stunning, and I'm not sure the XBOX can handle a hell of a lot more.
Conclusion: Succes of the game leads to succes of addons, not the other way around, and addons on PC are way easier to develop and distribute than addons for XBOX, or any console for that matter.

[Raw Kryptonite]

Flight sims have DLC, but they're called mods since they're (usually) done by fans, not the professionals who made the game. DLC is a mod pack that's put together by professionals who often need money to justify bringing it out, unless they think it will stimulate sales or maintain their customer base. Whatever the reason.

MS Flight Sim games and others don't survive for years based on the out of the box game. Most would die off quickly just like anything else if that was the case. Mods keep them alive and more up to date.
Also, players import planes from one generation Flight Sim (at least with MS back in the day) to put in the other one, so you've paid for another game, not much different than buying DLC. Then there are the expansion packs---that's the same as DLC, but you get the media.
DLC is nothing new.