If the underlying technology is poorly specified and confusing enough that it doesn’t get implemented well in 95% of cases, then yes, that does indict the technology. See also: PGP and email encryption in general.
But even if on balance the tech is worth implementing, it’s clearly not easy and your suggestions to “just” do several things that aren’t happening ring a little hollow.
I only used "just" twice, and they were both justified. Having people remember their email addresses, and explaining something in a couple of sentences, are both pretty easy.
Points #1 and #2 are not entirely trivial, but they're not much more complicated than the alternatives. A relying party has to store the public key counterpart to a user's private passkey no matter what. Is it really that much harder to associate that public key with their user ID? Point #2 is probably the hardest to overcome if you already baked in the assumption of 1 key per user. That's concerning. But that problem can also be mitigated by the authenticator, by supporting export.
I'm not saying the article fails to identify real issues. I'm saying it fails to identify insurmountable issues. The nice thing about software is that a good canonical implementation can be used by everybody for free.
But even if on balance the tech is worth implementing, it’s clearly not easy and your suggestions to “just” do several things that aren’t happening ring a little hollow.