First of all, they ARE getting traction. Many Youtubers and Twitch streamers started to use them in stream / video titles. I haven't seen corner barackets at all ten years ago, and these days I see them in use at least once a week.

Some programming languages also start adopting them, too. Raku is the one I know (it allows French and German quotes, too). Maybe Julia, too? I think some language communities tend to be more open to widespread Unicode usage in source code than others.