Buying 4 core sets is ridiculous, but I play a few games from FFG and hang out with a lot of people who play others. Realistically, if you want to compete, you need multiple cores for each of these games:
Imperial Assault
X Wing
Netrunner
Star Wars Armada
Star Wars LCG
Game of Thrones
Warhammer Conquest
I don't even know the rest, these are just games thatI know a large crowd who play them. All of those games, it is competitively all but a necessity to buy multiple core sets, sometimes 3+. I don't play Armada, but a buddy with a popular gaming blog was telling me after Wave 1 dropped and fleets expanded to 300 points, it became a must to have at least 2 $100 core sets. This is a game that didn't even have the self contained campaign that we have in the first box, and it's the same price.
I'm sure people will correct me. I don't play many games but I am close friends with many game crowds. I also will never buy 4 cores for this game, and I'm not saying you should. I definitely see the competitive value for owning 2, however.
Edited by Engine25