What would lead you to believe that in the last 13 years MS would make the titanic investment of reimplementing their (alleged) Google-based search backend?

Given the trajectory of Bing this seems unlikely.

For me it’s because DDG (aka Bing) results are vastly different than Google results. I use the !g and !s bangs often.

I think you’re making a huge assumption that nothing would change in 13 years!