I think I understand the theory behind your idea, as in not that a single person or a group of people be transparent and open, but that everyone do it at the same time. It can lead to interesting discussion.

I think it falls apart because it would also require the immediate disappearance of bad faith and mistakes. Let's say your real name is public. A bad actor could call up your bank, tell them your name, security questions (your dog's name or whatever, since the animal adoption records would also be public), your account number (which is already more or less public today), and get access to your money. If they don't do it right away, call back later with even more info and socially engineer customer support to get in.

Then there are marginalised groups of people who are in danger every day when they're in public because of race, gender, religion, etc depending on location. If all that was public also, they'd get attacked even more on the regular.

What about when someone is critical of a government that while public to the degree of your preference, is in a great degree of control over the population by means of public funding restriction or fines? The existence of that person or group would be inconvenient at best to them, so they could just find out everything about the group, track them down and disappear them. Yes, that would be public as well, but the rest of the population would be too scared to do anything about it.

Also for me personally, I'm not interested in the input of other people about how I live, what I do and how I spend my money. And definitely not interested in any ads tailored to me based on my data.