I wasn't suggestion browsers should compete with IDEs, just that consumer browsers and developer browsers should be different applications with different features, just like word processors and text editors are different applications with different features.

Regarding the word processor experiment, I don't really mean as something you'd use for one-off programming tasks, I mean as a replacement for a dedicated programmer's text editor. E.g., the point is that a developer-first browser could have features and developer-experience that consumer-first browser can never match, just like adding developer features to a word processor would struggle to match a dedicated programming text editor.