> Facebook probably will just be an archive 120 years from now. But a extreme long term policy will assist future genealogists. Something like "after 80 years past the death, all fb related data is available." after 25 years its available to direct line descendants.
This sounds highly troubling to me. Imagine being persecuted in your life because some ggggm whom you never knew about was an extremist (racist and what not - let your imagination run wild on how despicable that person was during their time). Your craving to learn about your family decades or centuries ago must not become an overriding factor for the entire society to abide by. The "right to be forgotten" [1], though not perfect, has a lot of value for humans.
On Facebook specifically, it is a highly buggy platform. Even as of yesterday, I couldn't get search to find recent content that I knew was there. I had to resort to other (slower and cumbersome) ways of finding it. This has been a long standing problem (several years). Content discovery in Facebook is terrible, and hence assuming Facebook to be the custodian of one's life experiences is a very, very poor choice, in my observation. Facebook is not the platform for archival!
[1]: https://en.wikipedia.org/wiki/Right_to_be_forgotten