I have no numbers to back me up, but my impression is that the majority of Reddit’s revenue comes from people browsing recently submitted posts, where they can

I have no numbers to back me up, but my impression is that the majority of Reddit’s revenue comes from people browsing recently submitted posts, where they can inject ads. Old posts/comments with technical or insightful information are surfaced via other search engines, not via browsing, so Reddit makes virtually no money from them. Deleting these posts and comments won’t hurt Reddit, only the people seeking information.