Because for its time, Gothic 1 and 2 were groundbreaking games.
Today we see them as these old games with crappy graphics and animations but back then nothing else could compete.
They were decent games, but hardly groundbreaking.
(Semi)-open world - does not come close to Daggerfall (1996)
3D graphics with third person perspective - implemented in Tomb Raider (1996)
Action RPG - made popular by Diablo (you guessed it, in 1996)
Interactive world - forging weapons, cooking - Ultima series had that a decade earlier.