There isn't an end to that, what is "all the data"? Someone will always want to record more data, and then sell it to someone. How do you force people to always reveal all the data they have. I think if you start peeling back the onion on what you're suggesting you will realize that it's not really possible or practical in any sense.
good point it does seem ambiguous in this context any data generated by me or any device I am using and any downstream data derived from that
why wouldn't this be possible? company x gives you y data and tells you we sold it to z and so on and you just follow the chain using some unique identifier
they sell the data openly and i get to see what they're selling win win legislation instead of annoying cookie banners
You deter them with risk that is too high for what they gain. For example, if consumers are awarded considerable fines for violations, then they would stop.