Dustan’s Comments

no, probably for the reasons outlined in the 1st three comments to that post.

but hey, if you manage to wrangle the amazing mess of code that it would require (the CSS would be hell), then let us know.

Alternatives:
https://www.meidell.dk/blog/archives/2004/09/04/nested-comments/
https://www.scriptygoddess.com/archives/2004/06/03/wp-subscribe-to-comments/
https://weblogtoolscollection.com/archives/2004/05/09/threaded-comments-hack-for-wordpress-12/

Thanks for all the replies! I’ll let you know if I eventually hack the code into a plugin ??