These Cybermen actually succeeded at things because they opted to not elect a Cyberleader. This was because during their first attempted invasion of Earth in the 1800s, they allied themselves with a woman called Mercy Hartigan who, after being upgraded to Cyber-King, destroyed the Cyberleader and rewrote the Cyberman software to make them far more efficient and successful. After the death of the Cyber-King the Cybermen lived on Earth and slowly rebuilt the Cyber-race into a fully-fledged Empire. At first, however, they consisted simply of ancient damaged Cybermen on the brink of destruction.They also made contact with the Cybermen of our universe and the two swapped technology, compared data and ultimately helped each other fight the Borg. The Cyberman Remnant provided the Mondasians with technology to prevent Borg Assimilation, in the form of nanobots. The Mondasians then supplied the rest of the Galaxy with this technology, redeeming the Cyberman name. After the two species of Cybermen made contact, the remaining Cybermen from the Parallel World dropped their Cybus Logo visage and instead opted for a simple circular pattern in their chests, a pattern which would be carved or drawn into the walls of tombs, sewers and caves for centuries to come.
When the Cyberman Remnant started to expand and develop their own technology, they differed drastically in the way they operated when compared to their ancestors. They abandoned their intergrated weaponry and tools and opted instead for handheld devices and large lasers that were far more powerful and could be used against more powerful races like the Daleks. At some point, the Mondasian Cybermen were completely upgraded to resemble Parallel Cybermen.
When the Cyber-Empire was established, the Cyberman Remnant was officially disbanded and renamed the Cyberman Military. Since the Cybermen were quickly rising to become the new dominant galactic power to fill the void that the Reaper-Flood Alliance, Daleks and Covenant had left following their respective defeats or changes, the Cybermen were able to generate enough resources to build a large army. In 2595 PLF the Cyberman Empire swore alliegance to the League Military and Leadership, and soon began their service of the League Military in their initial campaigns, all of which were successful.