You're arguing against the data. Care to continue doing so?

There are a few outliers, but really, the average page length is pretty low.

I'm running this right now, and what I'm getting is (5831 pages processed):

    mean:  3.9 pages
    median:  2 pages
    standard deviation:  11.06 pages

    5th %ile:  1
    25th %ile: 1
    75th %ile: 3
    95th %ile: 12

This is on a Debian GNU/Linux system with 3479 packages installed. I checked only English manpages under /usr/share/man (there are another dozen or so pages for openjdk under /usr/lib/jvm, max length 29 pages).

Obviously, mileage may vary.

Code:

    cd /usr/share/man
    time for f in $(find man[0-9] -type f -name \*.[0-9].gz); do echo -e "$f\t\c"; man $f 2>&1 | pr | grep '      Page [0-9][0-9]* *$' | tail -1 | sed 's/^.*\(Page \)//'; done

Compute statistical moments with your preferred analysis tool (I've got one I wrote for the purpose).

There are 68 manpages 37 pages or longer in length (2 standard deviations over mean). I see several shells (zshall, bash, tcsh), many perl utilities, and a few complex tools (mutt, openvpn, wireshark, busybox) among them. Pretty small count, actually.

Man pages were designed before a paradigm shift from systems oriented to user oriented design and are usually written in a manner that makes them easy to write, not easy to read.

While understanding a manpage's format is useful, ANY documentation which is "easy to write, not easy to read" is a bug.

As for alternatives to manual pages, I find the Linux Documentation Project's HOWTOs to be an excellent adjunct. GNU info pages, not so much.