People have made the same incorrect assumption that fido can't be backed up many times and it is a common misconception that halts adoption of the best security win since TLS. I feel important to correct this in tech circles so we start telling friends and family to setup a solution to the most common account loss problems.
Also, BIP39, the only backup spec that exists for FIDO atm, originated in the Bitcoin community where key loss is a very expensive problem that needed an elegant solution.
BIP39 can be used to backup any type of asymmetric cryptographic key that could ever exist in a human friendly way but sadly I am not aware of any vendors implementing it outside of hardware wallets which are general purpose tools
They can be used for PGP and FIDO and password management without using them for cryptocurrency and this is totally valid.
I absolutely agree that this is a thing that needs to be solved. I cobbled together my own solution using undocumented bits of the Solo firmware[1], but that's not nearly usable enough for average users.
But here's the problem: outside of the hype bubbles, cryptocurrency stuff does not have a good reputation. If the only thing that supports this markets itself as a cryptocurrency wallet, that is going to hurt adoption. People generally do not buy devices in which they actively do not want the main feature.
(I did remind myself of DiceKeys[2] while looking through my notes to find [1], but that has its own problems, such as "oh god what are you doing why does this involve OCRing a photograph of dice on my phone".)
This problem is already well solved and deployed to millions of people. That it is my point.
To your dicekeys example, a much better solution, IMO is using bip39-diceware which allows you to roll for 256 bits of entropy in the form of 24 BIP39 words with dice, using only a paper worksheet. You can use these with a KDF to determinstically generate any type of key material be it for PGP, FIDO2, mutual TLS, or whatever you like.
BIP39 is a general purpose innovation in human friendly cryptography, and so are the general purpose personal HSM devices that support it.
I don't feel it is productive to balk at a generally useful technology just because one dislikes the biggest audience creating demand for it.
Someone can have a religious objection to porn and still enjoy the bandwidth growth and other improvements to the internet that porn demand helped create.
Just because a toaster is marketed for toast, does not mean you can't enjoy it for pop tarts. Just because a pressure cooker has a "chicken" button, dosen't make it any less useful to a vegan.
The examples are endless.
Those that are fundamentally against experiments in decentalizated governance should at least try to appreciate that space presents high stakes security problems that engineers will innovate to solve.
Many of the best cryptographers in the world, like Dan Boneh and team at Stanford, spend a huge amount of their time focusing on innovations in privacy, computational effenciency, and cryptography to meet demand created by popular decentralized systems experiments.
If anything, buy products like hardware wallets that improve security for you and recommend their teams spin up marketing and product development approaches more inclusive of customers that have moral objections to decentralized governance and value storage use cases like yourself.
Okay, so first of all, you know very well that "moral objections to decentralized governance" is not the problem people have with blockchain technology.
But beside that, perhaps I didn't quite make the point of my comment clear enough. You're trying really hard to convince me of things. I know very well how this works, and what problems it solves, and I do think it's a good solution to this problem.
The main reason I'm not going to buy one of these isn't anything about the technology; it's because I already have a solution for myself and I have no reason to bother switching to another solution.
This isn't about my opinions. I'm explaining why the general public is going to continue to ignore this otherwise valid solution. The marketing around it actively ties it to a thing that most people have negative opinions of, and makes the feature they actually want seem like an afterthought. Even here, you repeatedly refer to it as a hardware wallet, because that has always been the primary focus of those devices.
The effect of this is that the average non-blockchain-person just sees you posting a lot of comments in a tangentially related thread trying to sell them on blockchain tech. Do you see why this, from the perspective of a non-blockchain-person, is counterproductive?
You will continue to have trouble getting people to adopt these devices until either the marketing focus changes or public opinion on blockchains changes. And one of those is going to be much easier to accomplish than the other.
I am not telling you this to bash blockchains. I do have negative opinions on that space, but I don't care to debate them here; nothing would be accomplished by either of us by doing so. I am giving you advice on the way your message is perceived by others.
Now your one time backup covers all current and future services.