Is The Google Indexing A Mistake Or Attempt To Be More Selective

You may have noticed a lot of content is now just discovered but not indexed on Google. This is happening for my websites and I see it all across this subreddit.

Is Google trying to be more selective and make people wait longer so they can't game SEO as much or is it a mistake (Google crawler broken). What are your thoughts and is there any official statement from Google Search on this topic?