I do agree with you that you should be able to freely exchange your privacy as you see fit. But the difficulty, as I see it, lies in determining whether the exchange is truly free or coerced by some means. The GDPR takes a strong stance on this (that consent is only freely given if withholding it would have no drawbacks) and it does have false negatives, i.e. situations where the exchange was fair but prevented.
However, there are two reasons why I think this is still reasonable (with 1. being more important):
1. The reality of the current situation is that invasions of privacy come bundled with other services, which you are pressured to use due to external factors. So I believe that the vast majority of cases are modelled well.
2. I see a privacy as similar to herd immunity, in that society benefits if lots of people have it, even if the individual does not profit from it directly. (In particular, it may prevent certain kinds of power from accumulating or centralising.) In these kinds of situations it can be necessary to restrict individual rights to achieve optimality.
However, there are two reasons why I think this is still reasonable (with 1. being more important):
1. The reality of the current situation is that invasions of privacy come bundled with other services, which you are pressured to use due to external factors. So I believe that the vast majority of cases are modelled well.
2. I see a privacy as similar to herd immunity, in that society benefits if lots of people have it, even if the individual does not profit from it directly. (In particular, it may prevent certain kinds of power from accumulating or centralising.) In these kinds of situations it can be necessary to restrict individual rights to achieve optimality.