100 hours in and no mods used, that's for another playthrough.
Part of the value is that the game is built to support mods on both PC and console, building and supporting that doesn't come for free so while it is community content is is enabled by Bethesda.
Part of it's value is that people are willing to work free, that doesn't come from Bethesda.
Well, it's free development so it does come for free.
Of course Bethesda enable free labour, why wouldn't they? they know from experience that they can throw anything out there and the fans will make the game they couldn't be bothered/weren't talented enough to make.