Google's John Mueller confirmed that Google crawls pages more often if they are more important and popular. So if a page is not crawled so often, that can be a sign that the page is not that important to Google. John said this on Twitter, "If we don't crawl then that often, usually that's a sign that we didn't think they were that important, which might help confirm that they were ok to remove."
He explained that this was covered in the Google blog post about crawl budget that reads:
Even if the crawl rate limit isn't reached, if there's no demand from indexing, there will be low activity from Googlebot. The two factors that play a significant role in determining crawl demand are:
- Popularity: URLs that are more popular on the Internet tend to be crawled more often to keep them fresher in our index.
- Staleness: our systems attempt to prevent URLs from becoming stale in the index.
It also reads:
An increased crawl rate will not necessarily lead to better positions in Search results. Google uses hundreds of signals to rank the results, and while crawling is necessary for being in the results, it's not a ranking signal.
But John specifically replied to me quoting the first part:
"URLs that are more popular on the Internet tend to be crawled more often to keep them fresher in our index." ?
— John ☆.o(≧▽≦)o.☆ (@JohnMu) August 17, 2018
So this is about crawling not ranking only? Of course, why obsess about this? :)
Forum discussion at Twitter.