I don't see how releasing a new core book would alienate anyone...
It wouldn't alienate anyone. But it would be useless.
EotE gives you all the rules needed for the shady illegal or quasi-legal activities.
AoR gives you all the rules needed for more formal conflict based games.
When it comes out F&D will cover all of the force related angles.
All the other possible settings/times do not require any new rules at all.
Now a campaign/setting guide that includes equipment, worlds/locations, timelines, NPC's/Organizations and so on unique to the specific setting is another matter. Those would be great. But 300 of the 400 pages in a Core is just repeated material.
A 100-150 page setting book for $30-40 is much better than $60 for the same 100 pages tacked onto 300 pages I already have, three times, in the other core books.