Technically can't find an event even if you have the full ID anyway, because you don't know the relays the event is in. That's why we have nevent1 codes and relay and author hints in tags. Choosing the relays for each client action is the most important part of Nostr but people have assumed that part away way too many times by hardcoding popular relays and expecting all events to be there, which works as long as we're ridiculously small, but kills the value proposition of Nostr entirely. It's like assuming Bitcoin will always be zero: it's only true if the entire project is a failure, and in that case nothing matters anyway.