As @jeff noted, the CONFIG_ALL_KMODS symbol merely alters the default selection so it only has an effect on a fresh, not yet saved .config since it will not forcibly select previous unselected kmods.
To retroactively enable it, you can use something like this:
sed -i -e '/^# CONFIG_PACKAGE_kmod-/d' .config
echo CONFIG_ALL_KMODS=y >> .config
make defconfig
Don't forget that some kmods are hosted by external feeds, so make sure that all feeds are updated and installed before activating ALL_KMODS.