I think that you guys think that the zoners dont have enemys and have nothing to do but if you read the history of the zoners carful you see that they have enemies and have a role in sirius like
exploring and trading to the Edge worlds ( following the wiki it says: These systems are a home to many of the most powerful factions and entities in Sirius, making them a dangerous place to travel through for freelancers and core world travellers. ( http://www.discoverygc.com/wiki/Edge_Worlds)
they have war with the nomads and the wilde that are located in the systems where they trade through
they are also the ally of the order and GMG so they are allowed to help them in their fight
and if you read the last sentence of the history there stand
It seems that Sirius is subjected to strong emotions that today's Zoners cannot ignore, but they are well prepared to face new challenges.
so in the furture they could have war with factions maybe gallia......
if these things not happen or the factions do other things ingame is something else but not a reason to change their fleet
so they had to and still have to fight for their neutral status and if that change they need that ships
and probably you start asking these questions because the actions of the ZA/ OSI/ Phoenix so then you should judge them and not all zoners because there also zoners that dont act like them but do what zoners should do