Thinking about e-bikes without inventing anything new you can protect the battery better from damage [impact/vibration/water] and you can design in a smart BMS [Battery Management System] that monitors and reports on battery cell health. The BMS could take action on its own to deactivate a battery that was out of spec so it could not be used in a bike or charged. That would at least force the user to take some investigation/repair action. The technology for both these items exists currently.
The enhanced protection would add to the cost and to the size of the battery packs. The smart BMS would add to the cost. At the moment there doesn't seem to be an interest in these improvements. Perhaps that will change over time as battery fires occur more often and get more press coverage. The Government could of course regulate this technology and require manufacturers to incorporate specific safety features.