This is a great point. And one I agree with.While I agree that FFGs making you shell out money for three whole books for what is pretty much "PHB split into sellable chunks" is stupid/money greed, I look at it this way.
If your story focuses STRICTLY on the Rebel Alliance, all ya need is the Age of the Rebellion books. If your strictly using Bounty Hunters, use Edge of The Empire. Clone Wars would be Force and Destiny+the appropriate Clone Wars books.
Basically the split book approach allows ya to focus on certain aspects of Star Wars you want or like. If ya want all aspects of The Saga, then yes the price is high.
Since I don't run "Jedi Games" I don't need (or want) anything from F&D. I can get by with AoR and EotE for everything I would ever want to do in a Star Wars game. And I can use that money from F&D to pick up some adventure resources/supplements and more fun dice!
FWIW I ran a whole campaign just using the AoR beginner box and the free adventure downloads/resources out there. Only cracked the AoR hardcover book for the adventure in it. Of course we used the pre-gens (even then, there are enough pre-gens out there on the intarwebz to satisfy most anyone as far as variety- and FFG is also easy to re-skin)