IMTU, stations vary
Where a system or the balkanized local governments "can't afford" a system-owned station
1) Stations may not exist
2) Stations may have been put in place by other organizations (Ex: due to shipping time and storage needs, LSP has put in place a "maintenance station" allowing their ships transiting the system can get support and repairs - [Secret: and also supporting operations either the local government(s) or Imperial authorities might disapprove of])
Where a system has a station in place, it is either:
1) A station some MegaCorp put in place with or without support of the local government
2) A station for which the locals cut a deal (and perhaps took out loans) to build/emplace
3) A station for which leveraged support was given by the Subsector, Sector or Imperial government
(even more explanations)
Stations that exist "now" may have been "purpose-built" and delivered in modules or whole, by megafreighters
Or, they may have started as a smaller stations to which module have been bolted on after the fact
In fact, in the older systems, you can likely trace the evolution of the station where you have the needed access clearance.
Based on the economics, you have to ask yourself:
1) Does the system provide an economic value to allow a station to grow and upgrade?
If not, then the station may be aging and there will be maintenance issues
2) Does the local government benefit enough from economics to be the power behind the station?
If not, what MegaCorp would benefit most from the Astrography of the system?
Are there other local competing resources?
(Ex: the D'Ganzio system[Spinward Marches] is the Sector HQ for InstellArms so they have multiple orbital logistics stations
Because of that, they not only will not have placed support stations in the Lanth or Ivendo - and, they might rent out
station storage warehousing to other customers)
Given the above, a game master has a wide range of "what does the local station look like?"