Comment by throwaway229864

This is an understandable concern, but it's not actually supported by the data.

On MacOS, where there has long been engine choice, Safari market share is >50%. Defaults are powerful and many users are happy with the real and perceived benefits of the first-party brand.

Safari has >90% market share on iOS today. If engine competition were permitted, they might lose a few percent initially, but would be highly motivated to close any gaps.

There's no world in which WebKit usage among the world's wealthiest consumers drops low enough that web developers can target a chromium monoculture. The purpose of engine choice is to create real competition in order to motivate Apple to do better.