> and in all that time I’ve never heard of Google not indexing a site. […] Google used to just index every site whether you wanted them to or not
Google can only index what they know of directly, or can indirectly discover e.g., by links. I have unindexed sites because, well, they're not linked to on the public Internet.
I can pretty easily see a 2 month old website being outside that; the question is does the rest of the Internet know about it? (And, the public Internet. A shared link in a Discord channel also isn't visible to search engines…) Some of the examples contain statements that indicate Google could or should know of them, but not all of them.
Google can only index what they know of directly, or can indirectly discover e.g., by links. I have unindexed sites because, well, they're not linked to on the public Internet.
I can pretty easily see a 2 month old website being outside that; the question is does the rest of the Internet know about it? (And, the public Internet. A shared link in a Discord channel also isn't visible to search engines…) Some of the examples contain statements that indicate Google could or should know of them, but not all of them.