I'm sure because handshake is such a system and there are many ways to skin a cat, and it's not a problem that I'd classify as 'hard' in a technical sense, such

I'm sure because handshake is such a system and there are many ways to skin a cat, and it's not a problem that I'd classify as 'hard' in a technical sense, such as useful quantum computing or terraforming Mars which both may or may not be possible. The hard part here is getting people to use it, the network effects. I do agree with what you wrote about the tradeoffs with the current solutions, but those are tractable problems, I believe.