I do replay older games sometimes, particularly the more arcade style ”pick up and play” games such as Ikaruga, many of which I have repurchased for PC in Steam sales. But mostly, I tend to keep moving forward as there’s always new games coming out.
Megadrive and Saturn emulation is fairly good now. I’m not sure where Dreamcast emulation is up to, but most of the noteworthy Dreamcast exclusives have been ported to modern systems (we just need a Skies of Arcadia remaster).
I don’t like having a bunch of old systems sitting around, cluttering up the place. It makes it difficult to move, they collect dust, take up valuable storage space etc.
Thankfully it seems that Xbox is striving to be backward compatible now, so I can just buy a newer system if I want to replay those older games again one day. For example, if I end up getting a Series X, I can (probably) replay Orta and Crimson Dragon on it. And I expect that the PS5 will be mostly compatible with my PS4 library. So, I think holding onto older systems is becoming less of an issue.
It would be nice if they could get Jet Set Radio Future working into newer Xboxes and the Ico/Shadow of the Colossus collection working on PS4/5. But haven’t held onto the older systems just for those games. There’s always YouTube/Twitch playthroughs if I want to revisit them.