In a perfect world I would agree with you; it would be really really nice if I could just play the world and forget about all the social stuff.
Unfortunately, rule books keep giving the DM more power and authority, and gaming culture puts more and more expectations on them to be the referee, social coordinator, and conflict mediator.
Yes, it is system dependent.
Again, I am not saying generalists or specialists are bad, merely that most systems have a sweet spot somewhere between the two and deviating too far from it can, depending on overall group composition, make for drastically weaker characters.