On the general premise, I agree. But I don't think that moment is today, not yet anyway. I don't think we understand the right way to approach context and memory yet or how long they should last for, never mind standardizing on an abstraction prematurely that ends up being like SOAP or SGML.
Fully agree. Any solution people think they have today is working on assumptions that are probably not correct. And things are still moving very fast.
What's better than SGML? What would XML an HTML look like if they were based on that instead?