Well to be quite honest, its not like you will have any real disadvantage. This isn't a multiplayer sort of game where people are gonna hop online and try to level the fastest. The way I see it, this is GTA and is meant to be a single player game in all of its glory. The added Multiplayer is very sweet indeed but I won't play it till my friends have it and that may be one day to a few days.
Unless you are gunning for the 100% complete club, then I could see why you are pissed.