>1 page front and back maximum.
Definitely Disagree.
It often takes longer than that to list which races, subrace, feats, classes, subclasses, and spells are not available. The campaign primer I'm working on has this section at 3 pages
And if you have anything specific to your setting or campaign that is being added, additional races, subclasses, backgrounds, whatever, you're gonna go way over 2 pages.
Then you may have like a page of houserules, or a page listing which optional subsystems are in use. Possibly a page outlining any changes to character creation. 2-4 pages
If you're only talking about world details, it's still too short. A page for the current region and relevant recent history, a page for relevant factions. A page for cultures, and a page for gods could also be warranted. So that's 4.
All of this is assuming one sided, btw.
So assuming you're not using a published setting, we're looking at 4 pages of setting info, 3-4 pages listing what's available assuming you don't allow "everything" or stupidly just restrict by source, roughly a page listing which optional systems are in use, a page of chargen changes if you have any, and a page or two of houserules.
>4,3-4,1,0-1,1-2,X
Thats reasonably 9-12 pages, plus whatever extra content your setting adds.
5-8 pages if you're using a published setting.