Yesterday, Google’s John Mueller said in a Google Hangout that, it is very rare when Google would not be able to find content, which is accessible on the web (except if it is blocked by web admin). He said this at the Google Webmaster Central office-hours hangout video.
Though, some time people asked in the forums that why google does not index page? But this type of incident is very rare. Where we can say that, the internal linking of the site was very poor or problematic. John Said :
For the most part it’s really, if you have a modern CMS, normal setup then somehow we’ll be able to find those pages. Obviously we can do better if you kind of move that higher up the chain but for the most part we we can find it. And obviously there are things you can do to improve that, where you can optimize it and make sure that it’s easier crawlable or harder crawlable.
Here Is The Video :