Possible incline based on what? They make games to appease shareholders.
Not quite - Zenimax is a privately owned corporation with private shareholders. The fact is they could whore their games out a lot more than they do. Skyrim has surprisingly little DLC.
This is worth bringing up. Anyone notice how Skyrim DLC are complete utter bullshit, especially compared to FNV DLCs? Gimmicky extra features with minimal content vs. four DLCs that expand the game in a lot of directions, they could be rounded up together as an expansion in the traditional sense.
People at Bethesda simply have no fucking idea on how to add value to the game.
Lucky for them, the shit they make just sells.
FNV DLCs were not only quality story, narrative and writing-wise, sometimes even achieving more than what a single, bigger expansion could; they also expanded gameplay possibilities, like The Sink, or unique equipment that was *truly* unique, and not a simple retexture (Stealth Suit, Holorifle, Red Glare, Sonic Emitters).
However, none of those features felt really "overpowered"; even top-notch weapons like Holorifle weren't viable for all situations and didn't make vanilla stuff useless, like those bullshit weapon packs or such. That non-mandatory content was useful, but not overpowered, and it simply expanded the alternatives. Of course, more quality content is better, and it's hard to expect an AAA game without DLCs, but it didn't discriminate the customer per se, in a "buy it or gimp yourself" way. Even the storylines were detached enough from the NCR-Legion war they didn't feel like they were necessary to compliment vanilla. They were just side stuff.
On the other hand, Dawnguard is a one, big $20 package of mandatory bugfixes. Without it, vampires & werevolwes are gimped forever, the "cool" features from that Bethesda modding session that were supposed to be in the vanilla in the first place, were shoehorned here and there, overpowered (Vampire Lord anihilating everything, Dragonbone Weapons being better than Daedric ones) and didn't bring anything worthwhile.
Every FNV DLC had a great, unique environment. In Dawnguard, we have vanilla resources over and over, except for a new gimmicky static here and there to make a difference, a bunch of dungeons that feel really "vanilla" and are even in Skyrim worldspace, and the only "unique" content, Soul Cairn, has absolutely nothing except for Arvak and Jiub. Just empty, lackluster copy-pasta. And Forgotten Vale is generic, overly long dungeon crawl with ridiculous Snow Elf lore rape.
And Hearthfire, lol