Bethesda should fully make it. Obsidian would only bankrupt and they like to make lots of bugs.
Also bethesda storylines are more coherent. obsidian makes better choises and consequenses.
What....? wait Obsidian likes to make bugs... Where can I order those.. can I learn them tricks...
Seriously:
Obsidian is only partly to blame for the bugfest that FO:NV
was at release!!. To be honest neither that engine or its illegitimate ofspring is any good at creating a rich questworld. The Gamebryo engine and the Creation engine have the exact same problems..
They both (especially on consoles) have huge memory issues.. (Framerate drops, freezes etc.. being the results) and both engines are not very well suited in assigning triggers in quests..
Both the quest issues in FO:NV (Veronica's, Ede's and Arcades quest triggers are just examples) as well as Skyrim.. (oh you picked up that one book that is actually a quest item... you fail) can be attributed to the engine as well.
The truth is even that Skyrim is I dare say, on all platforms combined buggier than FO:NV ever was.
Obsidian addressed most issues and gave extensive patch notes. Even addressing what specific issue on minor quests were effected by the patch. Obsidian also communicated more directly with its consumers, making use of twitter etc..
Bethesda's patch notes are very limited in description and some of those even don't make sense (the 1.3 Fixed the way radiant story assigns roles... note for example, nothing caused by radiant story was fixed.. visibly)
Bethesda's stories more coherent... I think you mean linear... at least Oblivion (Shivering Isles especially) did give you some branching in quests. Skyrim has has no choice whatsoever in Quests.. even if quests logically demand it.. (the werewolf option.. for example.. or ... the overuse of critical NPC's even if they don't have a role in the story anymore) etc. etc..
Don't get me wrong I think there is an unfair backlash against Bethesda.. but the truth is that they make/made inherently different RPG's than what Fallout was and what many (including me, though I can still enjoy FO3) feel it should be.
The only legit argument you are using is stating that Obsidian might go bankrupt..