I already have NV on Steam and would like to get it on GoG but I'm wondering if Obsidian still gets anything from sales. If it all goes to Bethesda (after GoG/Steam take their cut) then I won't be buying it.

Yeah thats what I expected. Oh well.

Purchasing can convince Bethesda to hire Obsidian to develop another Fallout game.

Hah! Fat chance. I doubt bethesda subcontracting obsidian will happen again.

No, they do not receive a dime because New Vegas received an 84 Metacritic instead of an 85 which was required in their deal to receive royalties. A travesty of justice because New Vegas is one of the greatest RPGs of all time, in my view.

Source: https://www.engadget.com/2012/03/15/obsidian-missed-fallout-new-vegas-metacritic-bonus-by-one-point/

It sucks indeed. But they kinda deserve it. The low reviews all complained about the vast number of bugs on release. I would hope Obsidian's takeway is that they need to do better QA before releasing their game but probably not.

While Fallout New Vegas deserves the title of one of the best RPGs of all time - that's only now after most of those bugs were fixed, not at the time of release.

That wasn't Obsidian's fault, blame Bethesda for not giving them enough time to polish the game by forcing them to adhere to the Waterfall development methodology(which means that devs have to release the game by the timeframe that the publisher specifies), which sucks for games and pretty much any software really.

Speaking of bugs, I had less problems with the vanilla game on the PC than I had with Fallout 3.

Even after all the patches Fallout 3 stayed buggy, occasionally making NPCs jump and bounce around like rabbits on steroids or stretch out like one of those old Stretch Armstrong dolls or Plastic Man.
And quite often I found stuff just floating in the air or when it is stuck suddenly lifting of like a rocket and disappearing over the horizon.

That sounds like a physic bug, make sure your FPS is capped to 60.

Oh my ... this is amazing I'd never seen this before THANK YOU.

Bethesda was responsible for QA/testing, not Obsidian.

Why is it always Bethesda's fault? If Obsidian could actually make a game that isn't riddled with game breaking bugs they might have actually got it out on time. They didn't, they never do and they have an impressive track history of sloppy badly made games.

They have an impressive track history of games being forced out the door to meet an impossible deadline, somehow still creating a game that far surpasses the game they're making a sequel to.

And you want to talk about bugs?
Skyrim is unplayable on PS3 to this day.
Fallout 3 was bugged to crap on launch.
Oblivion still has a glitch that will kill save files after 200 hours.
Shivering Isles launched with a bug that killed your save file after 1 hour.
Morrowind on Xbox required you to close every door behind you and only pick up items that you REALLY needed, otherwise your save file would corrupt, it would anyway, but this would speed it up.