The Corsairs and the Outcasts are funded by smuggling and pirating. This is significantly lower than what the Houses can bring in through taxes and corporate resources. Plus, the Corsairs and the Outcasts have a much lower population. They don't have the manpower to sustain a military as strong as the Houses.
As for the Corsairs owning the Osiris, it's not really that weird, but the argument supporting it is a weak one. It would be very unlikely that the Order, a faction dedicated to stopping the Nomads and the spread of Nomad technology, would ally with the Corsairs, a ruthless pirate faction that would kill another human without hesitation and makes the vast majority of its money through Nomad artifact smuggling. The only reason the alliance happened was because the Order needed Tripoli Shipyard, but there were plenty of other alliance choices for the Order to make if it really had to.
Carlos Rivera: Corsair Brotherhood Pirate - Retired, shifted to Tripoli Shipyard's Research and Development engineering teams Anthony Cameron: Guild Core Bounty Hunter - Killed in Action, committed suicide after being trapped in Omicron Minor following its destruction Juan Ruiz: Outcast Ghost of Razgriz Pirate - Killed in Action, killed by the Sirius Coalition Revolutionary Army during Bretonian piracy raid Michael Winchester: Liberty Security Force Agent - Missing in Action, likely killed during Rheinland espionage mission or trapped in Rheinland Space Eric McCormick: Order Pilot - Retired, shifted to planetside training of new recruits
