Fleet started as our attempt to explore a new generation of JetBrains IDEs, developed in parallel with those based on the IntelliJ Platform. Over time, we learned that having two general-purpose IDE families created confusion and diluted our focus. Rebuilding the full capabilities of IntelliJ-based IDEs inside Fleet did not create enough value, and positioning Fleet as yet another editor did not justify maintaining two overlapping product lines.
Ideally the fork should compete with Chrome and not Firefox for market share while acting as a hedge/warning against bad decisions from Mozilla and its leadership.