If hardware wallets became unusable, would confidence in Bitcoin weaken, or would people adapt with new storage methods? Is this even a possibility ?
Bitcoin has better issues to worry about than the hardware issue, as you would be able to import your Bitcoin into another wallet.
Although a reduced security concern may cause panic.
The unusability of hardware is not feasible, but if it happens, I am sure that alternatives would be provided or the issue would be fixed ASAP. It can't be permanent.