I agree. The base game is so in depth and long, you don't need the expansions, but as someone who did end up getting them after a couple of years with just the base, they're totally worth it, more so than the expansions of most other games I've had.
The vampire expansion was amazing. Not many games can say their expansions hold the same extreme level of quality as the base game as well as having multiple endings.
Source: My 2400+ hours in-game.
gta online is a garbage fireS
Source: my 800 hours in game