If you're not going to do any deckbuilding then I don't suggest getting any expansions, or only getting a couple of them. If you just add the new cards into the starter decks you're slowly going to bloat the decks to the point where they no longer function well.
Imagine Magic (you said you played magic) where you have your tuned RG destruction deck. It's quick and works well and almost every card you draw is valuable and helps you win the game because it's a part of your deck's theme / stucture. Then a new expack comes out and you take 10 new green cards and 10 new red cards and just add them in. Now your deck is bloated by 20 cards and those cards may not actually work in the deck properly because they may use different themes and have no synergy with the rest of the deck. Then another expac comes out and you add another 10 & 10…. now when you draw a card there's a 40% chance that the card isn't "in tune" with the deck and the game becomes slower and less focused.
Same thing with netrunner if you don't want to do any deckbuilding.
Perhaps you should slowly introduce the other players to deckbuilding and have everyone work together on making a new "default" deck with each expansion? Then you get to include new cards and everyone is still happy playing a known deck.