The bash manpage ... runs longish. 110 pages as 'man bash | pr". I do read it, frequently, though it's hard to assimilate in total andI constantly find new or unexpected things (after 20+ years).

Checking zsh by comparison: 6 pages, though a long "SEE ALSO" list with 10 zsh-specific entries, totalling 374 pages in all:

    for zsh in zsh zshbuiltins zshcompwid zshcompsys zshcompctl \
        zshexpn zshmisc zshmodules zshoptions zshparam zshzle; do\
            man $zsh | pr | grep 'Page  *[0-9][0-9]*$' | tail -1; \
        done  | awk '{tot+=$NF}; END{print tot}'