I'm not sure if that's the case.
I know at least a few people who just learned that Bing exists and switched to it in the last few weeks. This, of course, is just a random observation.
Anyway, Microsoft claimed in this March that they have now 100 million active Bing users [1]. It's a little compared to Google, but it's probably a huge success for them.
People already left the Bing Chat hype train?