Yup, even Digg is still around. Like you, I think reddit will be around for many more years. The content quality, which is already bad, will continue to get worse.
I didn’t migrate to Lemmy to help kill reddit. I’m here to help Lemmy grow. It’s already a better experience in some ways. Rough around the edges, and needs some features and fixes, but I feel like the user base is already much better than reddit is.