Look at costs per hour of play, estimate the percentage of "fun" hours and that is what it costs you to play destiny per hour, I'm in the "destiny costs me pennies" range, another $40 is likely going to net at least an additional 40 hours of play (likely 400 before the next expac) meaning the return on investment in terms of utility is through the roof, hell it is through the atmosphere. Look at it from the cost/hour ratio and it makes easy sense to spend another $40 down the road if you consider the opportunity cost of spending that $40 elsewhere and the utility you get from it, especially from the time you have sunk into this game already. Otherwise you have to consider the costs of producing the expansion (which btw, is not a DLC, this is like a game revamp from the look of it), it was likely in the 10s of millions, selling the expansion pack alone for $60 which would likely be reasonable considering the player base and costs involved with production. They instead decided to sell it for $40 which is likely them breaking even, the $60 version is the bargain offered to the new players, an attempt to get them into the awesome world that is destiny, and it will work considering what is put into the game. The only unsound financial choice Bungie has made has been it's lack of discriminatory pricing in regards to the digital aspects of it's collector editions, it should be offering the digital content from the collector's edition (which has impacts in-game btw) as a DLC for an additional price (5-10 dollars seems reasonable given the nature of the supply and the probable demand). You want the ultimate handout and bargain? Ain't happening, Bungie needs to make a profit and fund it's projects to continue producing awesome content.