IME, this is almost all players almost all of the time. Few players really want your campaign notes no matter how brilliant they think your campaign world is - half of the fun for them is exploring the world that you're building and so reading up on background material isn't something they're interested in. The handful of players I've had over the years who are truly interested in this stuff are players who are interested in participating in the worldbuilding themselves, rather than reading what I have as background.
Players who really want to read up on background material may exist, but I've never had them at my table. For most players that I've played with the only time background material enters the picture is either during character creation or when they want to know what background their characters may know about during an investigation scenario. Otherwise they're content to let the world unfold in front of them as they explore rather than do a lot of homework to immerse themselves in it away from the table.
