Is Ignorance Bliss
Consider this: Been in Sirius like 200 years and yet they still profess to NOT know where the Holes are or some of the pirate bases. The BH & pirates all still act like it's hush-hush don't tell a soul; not even your Mother.
I mean how hard would it be to follow someone to a hole. Or, heaven forbid, be creative enough to let a pirate escape & put a tracer in his ship. Or more simply put one on a BH ship that is being serviced or parked somewhere.
So, with that being the case during the last 150 years the pirates should have massed a large enough force to conquer any House system they so choose. Which, IMMHWO, would provide a much better plot than the pablum we were feed. OK. OK, it was not all that bad just a real woosy ending.
It is hard to soar with eagles when you fly with turkeys.