There might be arrogance. It depends on what the person has in mind. If it’s someone making a time capsule purely with the hope that someone in the future might find it interesting and delightful, then no, I don’t think arrogance comes into that at all. If it’s an ancient king trying to preserve his face and memory by minting and burying coins, then maybe you could describe that ‘arrogant’, but so what, it’s still great for the people in the future who discover it and get a window into a different time.