> current data points are much more valuable than historical data points, so storing old data doesn't have much incentives
Not true -- advertising profiles are vastly more valuable when based on a lifetime of data.
> also by having ability to enable/disable access to your data, you have the power of who gets what
But realistically, when are you ever going to disable access? If you want people to be able to read your replies no matter what social network they're using, you're going to make those replies available to every social network.
> and for which purpose also reselling of your data should become illegal to start with
This is my point. The solution here is legal, not technological. Personal data storage doesn't change anything legally, and changing the law would prevent reselling even if you didn't have personal data storage.
It seems important not to confuse the two, in order not to give people false hopes.
I agree that this is not just a technological problem to be solved. Technology by it self can't fix the problems, but it can help nudge the human experience in good or bad way. Right now, we gave our data to large corporations and we got the lovely attention economy thats being feed on human rage, envy and greed.
Solid idea is more in line with revolution and demand for our representatives to give their people internet that can push the humanity forward, and not just let us waist countless hours on doom scrolling.