But, unless explicitly stated otherwise and sans specific circumstances (honestly maybe even then), I believe data should not only be kept, but publicized, after X years. I want this to happen to my data.
The X years is necessary so people aren't killed for their secrets, and when those secrets contain information about living family and friends.
Ultimately, most of “history” and “archaeology” consists of such data. There’s a lot we only know because we non-consensually examined long dead people’s bodies, living spaces, even diaries. Similarly, there's a lot we can gain from online people's online posts, diaries, etc. in the future.
There are many tangible consequences why you don't want everything about you to be public or even exposed to "good" authorities, but I can't think of any that apply once you're long dead.
What happens to your online accounts when you die? https://news.ycombinator.com/item?id=42991112