With both Trezor and Ledger it is possible to use Electrum as the GUI (interface) app. So if they go out of business and/or stop supporting the specific hardwar

With both Trezor and Ledger it is possible to use Electrum as the GUI (interface) app. So if they go out of business and/or stop supporting the specific hardware wallet model that you own, you can continue using it with Electrum. Alternatively, you can import the seed backup (12 or 24 words) into a new hardware wallet.