And yet, I remain strangely optimistic ...

So here's how I think we might eventually get to a world of personal datastores, in two easy steps:

1. (In progress) More and more people notice that, say, health provider A and health provider B have their own data fiefdoms. That presents an opportunity to actualize paradigm-busting disruptive technology by combining them into a single, personalized, customer-focused data vault. Maybe the patient even gets to see what's in it, if that doesn't violate any privacy rules ...
   
2. People start to notice that they now have a health-records data fiefdom, a travel-records fiefdom, an entertainment-preferences fiefdom, a "who's connected to whom" fiefdom, and so forth. These are provided by several different entities, each with its own local UI customs and its own data model for nuts and bolts like names, dates, addresses, ratings and so forth. That presents an opportunity to unleash previously roadblocked potentialities, synergizing to achieve optimality by combining them into a single, personalized, individual-focused datastore.

This is great news. The VCs get two swings at the piñata instead of just one (as would happen if we went directly to full personal datastores), so who knows what kind of candy will fall out? We code grinders get to grind out twice as much code, and the research community gets to write twice as many papers. Win-win-win.

Doubtless XML will be involved at several points.

And lawyers.