Question for OP. What would be your guess that someone like he article writer is able to make the inference that Bing being down was also impacting DDG or Chat

Question for OP. What would be your guess that someone like he article writer is able to make the inference that Bing being down was also impacting DDG or ChatGPT ? Is it public knowledge that they use the Bing backend to do their work ? Particularly for Bing Copilot, isn't the relationship the other way around (OpenAI has the core sauce, bing uses its API to power their copilot searches) ?