In my (limited) experience sporadically uploading videos for fun the past decade or so, most Content ID matches simply makes a video ineligible for monetization

In my (limited) experience sporadically uploading videos for fun the past decade or so, most Content ID matches simply makes a video ineligible for monetization, and enables advertisements on the video. I think copyright owners can still block content, but most seem to allow it (with monetization redirected to whatever corp owns copyright) It's a hazy memory now, but I remember when the predecessor to the current system wouldn't block the video, but simply remove the original audio, and replace it with something from Youtube's royalty free music library. Did that actually happen, or is it a false memory?