I think the main reason why prebuilts don't make as much money is due to the fact the game has a small playerbase consisting of players who are willing to spend a lot (or grind a lot). These are the types of players who, regardless of your economic model, will probably spend a lot anyway simply because they love the game and want to collect and try out as many cards as possible. If the game and playerbase are to grow, eventually the game will have to switch out of this model.
Using the FF LCGs as an example, look at the Game of thrones LCG. Here's a link to the core set product:http://www.fantasyflightgames.com/edge_ ... =2&esum=71
In some locations you can buy it for cheaper (I've seen some locations sell it for $30). But anyway, when you buy the core set, you get 200 physical cards, and a lot of other physical components, but most importantly it's the same exact cards every time. You know what you're getting. The expansions (their equivalent of booster cards) usually cost $15, and you get the same 60 physical cards every time. No randomization whatsoever. Whatever you buy is also guaranteed to be immediately playable in a competitive fashion.
If I were to buy, say, an EX box for alteil, I'd be getting 60 predetermined digital cards for $50. The new half boxes in the shop give you 1 guaranteed card and 30 random cards for $10 (all digital). Throw in the fact that there's a lot of card chasing and rare chasing involved, and there's no doubt that in the minds of most gamers alteil is quite over priced. In terms of value, alteil compares very poorly to the rest of the market.
I understand not switching models at this moment, since the game will suffer economically. It's not as simple as, "switch models, and watch new gamers flock to your game." But new players trying out the game will leave due to the price alone (there are also other reasons new players are leaving this game, but the price is a big one).
Hence why I think the best course of action is to fix a lot of the other problems plaguing the game (to make the game more presentable), and then launch an ad campaign right after a new and improved economic model is introduced.