I won't deny that there were some questionable story choices made in Fallout 3, most of which have been discussed to death even more than Lamplight. It's admittedly a very uneven, and very flawed, game. I do think that most of the found text storytelling (terminals, etc) is excellent, but people don't seem to remember those as well as the dialogue portions, which are much spottier and certainly out-of-step with the established universe.
You name a total of two contemporaries, both of whom indeed have stronger writing than Bethesda. I wouldn't be posting here if I weren't an Obsidian fan, and Bioware was fairly solid up until Mass Effect 3, which had some abysmal writing, far worse than anything in Fallout 3. But here's the thing - this is an industry where, for many people, the peak of storytelling is Final Fantasy or Metal Gear Solid. Melodramatic, formulaic, closed systems with zero player choice. Bethesda might have stumbled a bit with Fallout 3, but they're certainly not trapped by linearity, and I'd say Skyrim is solid evidence of their narrative abilities. You might not agree, but that's your choice.
As for Bethesda's role in the aborted New Vegas content: let's just look at Alpha Protocol. Bethesda was in no way involved, and Obsidian was given almost six months of extra development time. And the finished product is still messy and full of holes and bugs. Not that it's a bad thing - I personally love holes and bugs. But it's clear that Obsidian has a tendency to tackle ambitious projects - and god bless them for it, because it gives them the chance to tell amazing stories with fantastic games, regardless of the rough edges.
Anyway, we're way off topic. Back to the point: Little Lamplight is okay I guess.