Regulators could ensure that detailed financial data of companies is public. If everybody understands how much profit and opportunities are in a certain thing that will encourage other people to do the same thing.
I always think that in this day and age financial secrecy benefits mostly the richest people and adds to the informational imbalance (which does not help even the model of free markets).
I agree, but its much more complex than just forcing companies' books to be open to the public. There are all kinds of accounting tricks you can pull with complex constellations of "entities" (the jargon used by tax dodge experts for the fake companies they set up). IMO we have to retreat away from a world where anyone with a couple hundred dollars can create a corporation by filing a form. Corporate personhood should be a privilege that is granted specifically by a democratically-elected government for well-delineated purposes and subject to revocation if the public trust is betrayed. This in turn obviously means that we need to establish (or re-establish, in places) democratic control of the government and, unless we do this all at once everywhere (very tricky) also massively reduce the amount of cross-border capital flows to the point where they can be reasonably understood and regulated by these domestic democratic governments.
All of this is a tall order, but there's no shortcut to establishing, re-establishing, or maintaining a democracy.
I think the idea of financial transparency should be more discussed at any level. Yes, there will be loopholes, but now the default is "money is secret, how dare you!".
I would claim that democracy was an ideal at any point in time. Most people have/had insufficient education to understand all the topics. Even in more advanced countries (with better education on average) the discourse gets focused on petty issues. The societies that will be able to focus on the longer term will be the next centuries winners!
To be clear: I agree. There is no reason that citizens shouldn't be able to inspect every document produced by their government, listen to any conversation about any topic that involves any officials, and no reason not to extend this regime into the so-called "private sector", which is -- legally and historically -- a creation of the state, not the other way around.
If you don't like that intrusion into your finances, you are still free to do business using your own personhood, but the public won't provide you with a spare disposable one.