If they want to keep our data, realistically nothing we can do will stop them.

I had the same mental debate when I deleted my Facebook account years ago and realized I just don’t have any power in this situation. I am deleting things mostly for my benefit; it’s symbolic, like throwing away the remaining pack of cigarettes. That act by itself does nothing, but it sure doesn’t hurt my chances of actually kicking the habit.

In this case, even if the data is still buried somewhere in Reddit’s servers, if enough people do the same it will destroy any “value” that Reddit has left as a company. Trying to undo all of that would be a massive, likely impractical undertaking that I’m comfortable betting simply won’t happen.

Depends entirely on the subreddit, in my experience. Places like AskHistorians didn’t even exist when the great Digg exodus occurred. My favorite sub was /r/cfb which also benefited greatly from the mainstream popularity.

Not coincidental that both of these are relatively strongly moderated compared to many of the biggest/default subs.