I'd give a key to my bank that they could create signatures with if I asked for (and was authenticated with) that third parties could trust to bypass my passkey. I'd pay a fee for it, the bank holds liability for verifying my identity.

Banks aren't perfect but mine already has all my money and the deed to my house. I trust the safety of my bank more than I trust Google not to lock me out or all my hardware to be destroyed.

OK, so your proposed alternative is to give a key to a trusted third party (TTP). But how do you authenticate to that TTP?