In fairness old age will do the same as the ones that will leave are likely the older members that started with more traditional forum software rather than more modern approaches that are pretty common outside of Unity. People just getting started now are much more likely to have been using it elsewhere.
My biggest concern isn’t that we’ll lose much of the community. It’s that we’ll lose the ones that are most valuable that can answer questions with extremely detailed answers. I know of a handful that are currently using the Q&A version of Discussions but I’ve only seen most of them here.