Corsairs and Oucasts own systems, planets, millions of people lucrative artifact and drug cartels which means they have an absolute tonne of revenue and resources for building capitals, not to mention both of them have one half of Sirius trying to kill them so it's pretty warranted for them to have capitals. Hessians practically own Dresden, 0-11, not to mention their guard system all of which have rich resources, in addition they are almost all former industrial workers and have experience with heavy machinery such as caps.
