There are real-world costs to information hoarding as well, when it's done by people who are not you and whose incentives are not aligned with your own.

I'm glad that data is rotting on the Internet. In fact, I'll go one step farther and say that data should rot more quickly on the Internet. There's no reason that some scummy marketing algorithm should have access to my high-school social media posts. There's no reason that governments or private individuals with a grudge ought to be able to through the history of everything I've written, no matter how off-the-cuff, in order to dredge up something that makes me look like an undesirable when it's taken out of context.

If an individual wants to save a particular piece of information, that should be their choice. Otherwise, by default, information ought to disappear from the Internet.