"Google is no longer trying to index the entire web. In fact, it’s become extremely selective, refusing to index most content. ...it’s a fundamental change in how #Google approaches its role as a #searchengine." https://www.vincentschmalbach.com/google-now-defaults-to-not-indexing-your-content/
@Guinnessy would love to see some empirical underpinning for this. Like comparison, for a few small sites, of Google search results with results from the sites' internal search engines (if these are reliable ones).