Ask HN: Should Apple move to biennial iPhone announcements?
No synthesized answer yet. Check the discussion below.
It's also about iterating on internal capabilities, processes, technologies across design, sourcing, manufacturing, etc.
What makes it into each year's phones is what's had the kinks ironed out, and all the commercials sorted.
https://storage.courtlistener.com/recap/gov.uscourts.njd.544... (point #14)
16 -> 16s -> (17 + 16s /w discount) -> 17s -> (18 + 17s /w discount) -> ...
I'd even say that the Pro could be it's own line. The unibody aluminium and tweaked looked would've been a good starting point for "iPhone Pro". (then iPhone Pro 2, 3, 4...) That could free them from having to segment the market for every single iPhone release by "pro" features, since the new pro in theory might only ever need a biennial release.