Legacy mode will be phased out as soon as it has served their purpose of smoothing over the transition.
Or, it will be allowed to die of neglect, slowly becoming less and less compatible with the site until fully unusable.
I miss old reddit, nothing else really fills the niche in a unified way.
Reddit and Facebook both have some hold for me because of niche communities that they both let me aggregate/monitor/interact with easily, without going to a myriad of websites. I really don’t want to have to do that - in some cases, I’m not even sure I can find comparable replacements.
It is interesting because it's related to what I do but different enough to be fascinating.