It is nothing like emergency, you have your hardware wallet like Trezor which you can even access with different wallet software like Electrum for bitcoin, Metamask for ERC20 etc, even if the official software of the wallet is outdated, you can use other reputable software wallets to spend your coins.
That's true, but don't forget that OP used an imaginary scenario in which they have 15 different cryptocurrencies. You have covered bitcoin and ethereum with Electrum and MetaMask, but what about the rest?
Trezor should really improve their website and the page that shows supported coins >
https://trezor.io/coins. The source doesn't show what alternative 3rd-party wallets work in connection with Trezor HWs in case you don't want to use Trezor Suite. Do they compile this information somewhere else?