Because whoever is left in the Home Worlds is not going to be disgraced. If you look at who Vlad left in the Home Worlds, he left a arse kicker to look after Wolf interests. Further, its likely the Wolves left frontline clusters in the Home Worlds during the Invasion.
But the point was- there should not have been a break down of communication that left a Star Captain as the most senior member of the Clan left. Even if you swallow no Star Colonel survived on Wotan, you still had the Red Keshik's Galaxy Commander John Ward (Delta Galaxy Command), Delta's 4th cluster, Epsilon Galaxy- Green Keshik (Galaxy Commander Anton Fetladral), Star Colonel Jewel (Choyer), Star Colonel Sanal (Dorbeng), Star Colonel Jersano (Gurbeng), Star Colonel Evon (Nega)- who had ristars or oldsters as officers (Evon becomes Evon Ward?), plus other clusters like the 24th Rangers Cluster (frontline, Obj Raids), 9th Wolf Guards (frontline, Pouncer fluff), and whatever Lajos was assigned (last BoK book). Further you have the rest of the secondline & garrison galaxies besides Tau, Epsilon, and Omega- who never saw action in the Refusal War.
Command on Wotan should not have broken down- the odds of all Star Colonels dying at once while in combat is laughable. None of the Tau (6), Delta (2), or Gamma (2 + Bronze Keshik) officers survived to maintain command. The only Star Colonel we know that survived on Wotan was Star Colonel Marco Hall, who retreated off planet with the remains of the clusters of Natasha's spearhead (3rd Battle, 13th, 341st, 352nd) along with some who were in Ulric's spearhead (Bronze Keshik, 37th, 11th Guards, plus individuals). Some like the 11th Battle ended up Wardens trapped on Wotan, who were bled out by Vlad. In the Clans, the next warrior is always ready to leap into the still warm shoes of a superior officer.
