Edit: my original comment wasn't very constructive.
My issue with the analogy is that Xiaomi openly copies the design of competing products that have gained success, at least in part, due to having differentiated designs. Usually they copy without providing even incremental innovation or product differentiation.
In the case of Sublime Text vs. Atom, GitHub developed an editor with a fundamentally different underlying architecture. Github also made Atom open source, which addressed one of the main complaints against Sublime Text. Atom offered obvious and non-trivial product differentiation.
Also, Xiaomi specifically targets products that have distinctive designs. Sublime Text's design doesn't look that distinctive. What are the components of the design (excluding configurable parameters like a light/dark theme) that Atom copied? The main similarity I see are the tabs, but neither look distinct from most other tabs (i.e., Chrome browser tabs).