I've been on reddit for 13 years. My wife finally got an account last year. She cannot understand any of the fuss. She didn't know there were apps outside the official app. She never used RES. She just scrolls and never comments or posts. I would be surprised if she even upvotes or downvotes. She's not a monster, she just doesn't reddit like I do.
95% of users are like my wife. 5% of users are like me. I haven't even tried to explain this whole Lemmy/Kbin experiment to her yet.
But the thing is, if 50% of the 5% of us who are active posters (e.g., 2.5% of total users) are now over here on Kbin/Lemmy, the 95% who are left are going to notice a huge difference in the experience of the site. Conversations will be dull. New posts will be more ad-focused. They may not be able to explain what happened, but they will notice that Reddit is not as fun as it used to be.
Will this stop spez from getting stupid rich? Probably not. Will my wife switch to Lemmy or Kbin? Never gonna happen. But the people who want to be part of the old culture will find their way here. The stuff that made reddit great is already happening over here. Reddint will not die anytime soon, but it will cease to be relevant. Think of how long yahoo lasted even though no one cared about it. Reddit is going to be like that.
I haven't yet deleted my reddit account. It will probably happen. But I also haven't missed it. I've actually been excited to come over and see what's happening every day in the fediverse! I'm posting more, and considering modding for the first time.