I think there should be some incentive for that, like make those kinds of comments a spotlight or something. Maybe make a community called “late replies” that showcases the best such replies, or have a rule saying they grant free karma (in Reddit’s case).
Its not a global bump, but it does bump it back into conciousness for the person being replied to. Ive had it happen a few times on lemmy, and its always so confusing because i had completely forgotten what i had originally said.