With most of the old ranges still running, I fail to see how GW benefited in anyway from axing WHFB, and a lot of ways in which they hurt themselves.
The problem comes in with market share and product marketing mix. If you have one product line that has a shrinking margin due to volume sales in steady decline, it doesn't make sense to continue to divert firm's resources to what is essentially becoming a loss-leader for your distributors and retailers (FLGSs in my area are still trying to get rid of the WFB NOS/Backstock). Especially when we can see that there is a larger demand for the firm's other product lines (40K, 40K boxed games, Horus Heresy). GW takes a lot of flack for what people call "bad business decisions" which are actually quite brilliant business decisions considering that they're a successful company competing in a niche market, which also competes against the much more vast hobby and entertainment market as a whole. These people not realizing that their opinions are fueled by emotional subjectivity-- a product of brand affinity and marketing-- not objective understanding of marketing, business and finance. Ultimately, at the end of the day, GW is publicly traded and has to answer to its shareholders at the end of each quarter. As a shareholder, I would have to wonder why a company keeps investing my cash-flows into a product-line with a shrinking margin and ROI, instead of a) paying that cash to me in dividends, b) diverting it to one of their more profitable product lines or c) starting a newer more-attractive-to-new-customers product line.
AoS appeals to (regardless of what us more seasoned gamers-- I will not say old-- like to think) the younger future life-long gamers coming up now. A generation of gamers raised on Pokémon, Halo, MMOs and CCGs-- I don't have anything against these things, except maybe CCGs, but even as I write this I am googling for Charmander and Squirtle spawns in my zipcode for Pokémon GO.
What would be really sweet is if someone could do a little bit of investigating, maybe get a kick-starter going, and do what WotC/TSR did with 3.5. See if they can get GW to license them the system and other associated IP and maybe some of the molds(!) to produce an open-license version. Look at the popularity of Pathfinder, it can be done, there's a precedent for it.