Fixing a Gesture-Only Archive Action in an Email App

A mobile email app lets users archive an email by swiping it left in the inbox list. There is no visible archive icon anywhere in the row, no swipe hint shown on first use, and no way to archive an email from within the open message view either — swipe-in-the-list is the only path. Usage data shows the archive feature has near-zero adoption among new users, despite being a heavily-used feature among users who migrated from a competitor app that has the same gesture.

1. Diagnose why usage is split this way between new users and users migrating from a competitor with the same gesture.
2. Propose two specific changes to fix discoverability, and explain what each one does and doesn't solve on its own.
3. Is there a design reason the team might have intentionally left the archive icon out of the row? Weigh that reason against the adoption data.