> why aren't they "here" in popular adoption? I think, although it is perfectly technically feasible in a vacuum it is not in real life.

HN is likely not the best forum for this argument, but I'd have two answers to this:

1. Email is popularly adopted. It's difficult to add improvements because it's a federated protocol from the 60s, but it is still popular.

2. The reason we haven't had popular adoption since is because: (a) email was publicly developed, whereas most newer tech is private; the market favours easy (cheap) over better (hard, expensive) and federated is harder to do (with worthwhile benefits); and (b) the major downside of centralisation -vs- federated is vendor lock-in, which is bad for users but good for shareholders.