I doubt SE would ever been this transparent about the cash shop but imo the cash shop provides the following resources, it's what allowed European Servers to exist, physical merchandise to be made and Fanfest to occur. If you just went by the subscription alone and did nothing else to gain support from the fanbase odds are there would be no funds allocated to do the above, especially the next big change, server upgrades with the dropping of the ps3.
Though I am pretty sure at one point they did comment how it's the cash shop that does help support the drive to do fanfest because when they see the support of fans purchasing merchandise for the game and gaining in-game items, it shows there is a market in which they will be able to sell out tickets for their fanfest.