Then, you make some sort of lifetime guarantee that you'll keep up with changes in storage and interface technology. Guarantee that the thing will be later upgraded to seamlessly translate people's wedding photos to the next big image format. Guarantee you'll keep it forward and backwards compatible to future OS updates. Guarantee it'll work with future phones and tablets, etc.
Maybe even build in some kind of automated off-site backups in case of fire, theft, flooding.
If you made it simple, and if you earned people's trust that this is really an investment - I think you could really clean up with local home storage.