I've been going through the backlog of "old" Dateline episodes on Peacock, and they actually used to update existing episodes from past seasons just like they do now - but they didn't market them as new. For example: you're watching an episode that originally aired in 2011 i.e. 10 seasons ago, and there's a couple of minutes with new footage and voiceover added. Again, similar to how they're doing that now, but they don't call them new episodes and put them in the current season.
And yes, I feel like they're focussing too much on prominent cases. Happens too often in the current true crime media landscape (goes for YouTube as well). That's why Cold Justice (at least where I'm at - season 3) has been a real refreshing show for me.
