First-order effects

• Developers with 32-bit Mac apps lose the ability to submit new apps or updates to the Mac App Store after January 1, 2018, forcing a 64-bit rebuild or abandonment of the storefront channel.
• Mac users relying on long-neglected 32-bit titles face a shrinking catalog, since unported apps can no longer be newly listed or refreshed.

Second-order effects

• Publishers without resources to rewrite for 64-bit exit the Mac platform instead — Twitter's decision to stop offering its Mac app weeks into the new policy shows the cutoff accelerating withdrawals that might otherwise have lingered.
• The deprecation sets up a second deadline downstream: once Mojave ends 32-bit runtime support, previously purchased 32-bit apps stop launching outright, converting a developer-side rule into a user-facing breakage event.

Third-order effects

• Apple normalizes scheduled obsolescence across both of its app platforms — the same logic resurfaces in 2022 when it warns it will remove apps not updated in a significant amount of time, giving developers just 30 days — making continuous maintenance a structural cost of distribution through Apple's stores.
• If the pattern holds, App Store compatibility becomes a rolling treadmill where Apple's OS cadence, not developer choice, dictates which software remains available — concentrating distribution power further in Cupertino's review pipeline.