Back in the early days of Redhat, rpm's didn't really have good dependency management. Yes there were rpms, yes you could download them, but getting the full dep tree was a PITA. Most people installed the full Linux distro rather than a lightweight version because of this.

Debian's apt-get was very "apt" at the time when it came out. It solved the entire issue for Debian. There was a point at which there was an apt-rpm for redhat. Yum tried to solve it for redhat, but didn't really work that well -- particularly if you needed to pin packages to certain versions.