Interesting. Either the quarians ripped out only some of the system's internal systems and neglected to remove the significant central computer core, valuable Element Zero core, and station VI or as T'Lainia earlier speculated the station was unfinished. The station being incomplete seems to be the likelier option but the presence of an Elcor plushie suggests there may have been children aboard and you wouldn't bring kids aboard an installation that is still under construction.
The presence of a VI is additionally strange if this were a quarian facility that was evacuated during the Morning War. The lack of damage from weapons fire suggests that those aboard the station should have had sufficient enough time to delete the VI before they left. It is possible the VI is indeed a Geth though unintelligent due to the lack of other programs to interface with and or reset to factory defaults but that seems unlikely given the nature of the fighting during the Morning War. The fact the station's VI wasn't purged combined with the presence of an Elcor plushie makes me think this might not have been a quarian station at all but a Citadel aligned one instead.
If you take a closer look at the translations made of the discovered text then you'll realize that there's nothing that outright states the station is quarian.
1: evacuation order given. 2: citadel council refuses to render aid. 3: geth platforms begin to rebel across local worlds. 4: station central command.
The Citadel could have been the ones to order the evacuation. The worlds the geth are rebelling on aren't referred to along the lines of 'our worlds' but as the more dispassionate local worlds. The second translated sentence is the closest to implying that the writers are quarian but even that on further reflection can be interpreted as a statement of fact of the Citadel's reaction to the ongoing crisis. Alternatively it could be that the Citadel was stating they would not aid in the evacuation of the station itself which would explain the rather hastily and incomplete strip down of the station.
All that said I still find it odd that station's life support systems were active as was it's artificial gravity when it was discovered by the Hestia crew. Why weren't they shut off and how were they running without maintenance and resupply for possibly centuries?
Of course, given replicators, I'd expect to see copies of the thing popping up before too long
It's funny to imagine every child aboard the Hestia eventually having their own Elcor plushie and the reactions of the Citadel races to that revelation.
The dilithium is to be expected, but the lithium makes me think that the Old Quarians were new here and they hadn't prospected the system yet before the Morning War, or that ME sensor tech is much worse than Starfleet standard issue even without the whole "all ME sensors are slower than light while ours aren't" thing.
Most likely the former, ME sensors should be enough to pick up notably high resource concentrations. If they weren't at the time of the Morning War they should be by ME's 2180s.
Given the limitations of Mass Effect's method of FTL travel it is not unreasonable for local resources to have gone unexploited. Any mining operation in the system would have necessitated regular traffic to and from it and thus warranted the presence of a fuel depot. Finding out what purpose the station served will help answer this question. For example if the station was a lone research outpost then it explains why there was no mining done in the system as it alone wouldn't have been able to support such a presence.