@HappyPolygonRS is now the default c4d render engine. This doesnt necessitate the removal of the older render engine as there's little harm leaving the feature as it is, but they naturally will get removed at some point in the future I imagine, probably not this side of 2030 would be my guess.
@davetwoOctane is my full time engine, once a year or so I give RS another poke to see if its worth switching, but it isnt there yet from my POV. That said, its numbers will naturally keep expanding now that it is the defacto c4d render engine. The biggest issues for me is that I can keep octane running smoothly with almost any scene; when RS starts getting busy it has a habit of bogging down the entire c4d UI like the old cpu engines used to do. Or you change a material setting only to have to sit there for an entire minute or so whilst something somewhere updates and recalculates a cache.
RS is going in the right direction, im just not sure if or when it will surpass the ease and speed at which I can work in octane. Their best bet imho would be trying to trump octane in other areas. Give me a stable art directable engine and I would have reason to use it, but if theyre only chasing realism and speed, im not sure they will ever take the lead there.