Trickster Spirit
Explorer
I agree: you could likely produce one rulesy hardcover a year for 5E and that would be plenty for rules support. But then you could add an annual setting hardcover (FR one year, then Eberron, then Planescape, etc...) and quarterly setting gazetteers. Throw in bimonthly self contained modules and a monthly periodical ( print or digital) and it would be just about right. Bloat only happens with rules, and only then if they are incorporated into the larger publishing strategy. Everything else is an option.
Has it occurred to anyone that they have looked at survey feedback, private focus groups and sales figures from 3.5 and 4E and just decided that campaign setting books won't sell terribly well?
They didn't do quarterly campaign gazetteers in 4E when they did release a lot more product, why would they for 5E when they're deliberately releasing a lot less?