Google has definitely just plain delisted a lot of older sites, even if I do exact quote matches I can’t get results for sites I know exist and used to be indexed and often turn up on other search engines.

On top of that, as you say, anything that isn’t from a huge web property or corporate site is so heavily penalized you’re lucky to ever see it even if it is new.

The utility of google as a web search engine is definitely declining over time.