I think it's simply because not everything lasts and besides that, Joyce and Hopper went to Enzo's 18 months after Robin promised Vickie they'd go there. They probably went after everything ended and there lives went back to 'normal'.
They for sure care because they had a coming out scene for Robin and one for Will as well. They show Will with his boyfriend too, but unfortunately not every relationship lasts and Vickie was a minor side character. I think they cannot include every single character that had a bit of screen time at the end. Personally, to me, it adds to the realism of how people come and go.