I would not say it's likely to die because it's obviously false since on iOS it's the only choice but it's true that when you see the release logs of Safari, it's moving very slowly very far behind Chrome or Firefox.

Safari has 15% of the browser market share (https://gs.statcounter.com/browser-market-share) (including mobile). WebKit will probably be fine for the foreseeable future.

Anyone on macOS who values battery life and system responsiveness.

iOS users