In terms of the number of NPCs going about schedules and physics objects that keep their states persistent throughout the game, I don't think any major release in the market is at the same scale of Elder Scrolls.
There maybe other games that do certain things better or have technically bigger worlds, but the number of AI and physics things Skyrim has to keep track of is still way beyond Witcher 3, Zelda, Ubisoft games, and Rockstar games. Not just the number either, but the fact that the game has to record any and all chances to the states of those things and remember them forever. Finally, I think Skyrim had a smaller team working on it than Witcher 3 or Zelda.
In my opinion dealing with bugs is actually a matter of how much you're willing to put up with divided by what the game offers in return. Arma 3 is probably five times buggier than Skyrim (it's the same tech as DayZ if you want a frame of reference) and I've still put almost 300 hours into it because in terms of scale and AI interactions it's far beyond anything Call of Duty or Battlefield have ever even dreamed of trying. I can't get this type of shooter anywhere else so I keep playing Arma. Millions of people still play Skyrim because its range of physics and AI interactions provide for a sandbox role playing experience you still can't quite get in Witcher 3, Zelda, or really any recent major release.