This is probably my biggest fear. One day Apple can revoke my certificate, and suddenly my apps stop working for everyone.
"One day," Apple could do anything. One day, they could totally prevent installing things that are not notarized. One day, they could entirely prevent non-AppStore, non-sandboxed applications from running on macOS. They haven't, but they could and indeed all signs point to these being on the very long-term roadmap. Does this mean you stop writing Mac apps today?
This has in fact happened: https://blog.charliemonroe.net/a-day-without-business/