Fewer portable titles would be a good start. Add to that, every other portable release is outsourced (i.e. the "Oracle" GBC titles). A quirky, unique follow-up like "Majora's Mask" could be created for each new engine - varying in tone from the major releases, but being only a tweak on the overall visuals.
There is no reason, following this sort of strategy, that Nintendo could not conceivably release full console "Zelda" titles at two and three year intervals (3,2,3,2). Even a change of that sort would mean double the number of major releases in a given decade.
Nobody is asking for annualized "Zelda" games, God forbid. It would be nice to get regularly released ones, though.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."
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