I'll concede that it's not nearly as crazy to share keys across devices for home use or low-risk things. I must admit I was speaking mostly from an enterprise perspective.
I could see this eventually being built into 1Password's Secrets Automation product which can sync to each user's 1Password client. It allows the use of Vault for a backend so now that SSH Keys in 1Password are a thing it wouldn't be out of the realm of possibility to have Vault generate short-lived per-user SSH certificates that are automatically rotated into the user's 1Password vault.