Actually the answer is that
dpkg package manager cannot install dependencies out of the box. You cam
man dpkg and found that out. So you need to use tools like
aptitude, ..., based on
I would say just the same case is for the
rpm package manager on the other Linux hemisphere.
rmp is not meant to do dependency based installs. It can install single packages, and for installing the dependencies you use
up2date these are all based on RPM.
As noted there is a slight danger installing packages with
dpkg directly, because later dependency resolution resolving may end up with a broken system as @Rinzwind outlined.