Well, switching to NSFW not only limits their revenue to to their self-declared restriction on advertising in those subs, but - and I think this is more important - those subs go dark for the purpose of reddit’s front page. They made the change a couple years ago to exclude all nsfw subs from r/all. There was no need to; r/best was already r/all without the NSFW subs. Any sub that is excluded from r/all is invisible to the eyeballs which pay the bills because that’s the default home page.