I'm not sure if this is research quality or product tuning. I tried using Bing's chatbot and I found the experience to be vastly worse than OpenAI's version, yet Bing is ostensibly running on exactly the same platform (GPT-4). I think OpenAI turned the dial to "loquacious and friendly" and we humans are interpreting some pretty-similar underlying tech as having vastly different underlying quality, because we're impressed by that sort of thing.

The user interface to a tool matters.

Once you're down to user interface, you're no longer in "insurmountable technical advantage" territory.

But more critically, chat.openai.com is more of a tech demo than a serious product. So one can optimize the UX for "chatty and engaging" without being too concerned for accuracy. Bing, on the other hand, is intended to be a search product. It's noteworthy that adjusting the same model to provide a more accurate search experience seems to have snuffed out a lot of the magic.