They did work like this? News to me.
One Yahoo mailing list (I replaced with Discourse) would send from the-group@yahoogroups.co.uk so if you saved this address and attempted to send a mail to it, it would have done exactly the same thing?
I believe you can and should already set this up and is determined by the person who manages the domain and the email service account - usually the admin.
On one of my sites I occasionally get even fairly tech savvy users replying to the noreply@blah.com notifications because the email ‘from’ name uses someone’s account name which confuses them.
However, if your admin has set up reply-by-email, that will work as described - it will reply to the topic!
I don’t think this is a bug, isn’t this simply a misunderstanding and misuse of the functionality and risk of enabling this feature?