Meanwhile OpenBSD running all the default network services like sshd and smtpd uses < 32 MB RAM and that's with full ksh and real tools. That doesn't happen by accident.
Is that fair? Busybox has fewer features than OpenBSD coreutils but those in turn have fewer features than GNU coreutils. All three implement the entire POSIX spec as far as I am aware.
Meanwhile OpenBSD running all the default network services like sshd and smtpd uses < 32 MB RAM and that's with full ksh and real tools. That doesn't happen by accident.