Back when Chrome was the new kid on the block and people were switching to it from Firefox, Chrome gapped Firefox super hard performance-wise pre-Quantum/e10s. Firefox was still a single-threaded browser that would lock up if a tab had particularly nasty JS. The extensions also broke all the time because while XUL extensions could do anything, even tie into the actual browser frame, that was a maintenance nightmare that made it difficult to change anything and even harder to parallelize.

In the post-Quantum era here in 2023, you're definitely right that there's no real reason to switch from Firefox to Chrome. The practical performance gap has been closed, the extension system has stabilized and offers more functionality than Chrome's implementation, it's not actively trying to sabotage adblockers and anti-tracking measures, and is just all around better about privacy. It's time to call the powerusers and techies home.