Comment by carlwgeorge

DNF didn't start as a competitive fork of Yum, it started as the Python 3 rewrite of Yum from the same developers. It was really just Yum version 4, using a different name so it could be installed in parallel with Yum for an extended period of time. Yum changing algorithms was never on the table, as that Python 2 code had to get phased out. Fedora, CentOS, and RHEL switching to it was always the plan.