This might be a promising step, but you still have the problem of a) the data exists b) people are highly incentivized to get the data. Ban selling it? They'll

This might be a promising step, but you still have the problem of a) the data exists b) people are highly incentivized to get the data. Ban selling it? They'll share it. Ban sharing it? They'll form byzantine corporate structures that make it not-really-sharing. Or they'll just do so informally. If you want it all to stop, that means banning the collection of data. This of course won't eliminate it altogether, and it will wipe out a lot of the tech industry, but it will go a long way, and proving someone has collected data they weren't supposed to is a lot easier than proving they shared it inappropriately.