Marine prices solution also seems to work, though supply prices up to at least 300 are still possible.
Dissidents should not affect Supplies:
http://starsector.wikia.com/wiki/Market_conditions (as this is the vanilla wiki, this is obviously not taking possible mod changes into account, no idea what and how many market conditions are mod based and create demand for supplies)
All you're doing is limiting what size markets are allowed to get that specific condition (or it just limits the market size entirely, but that seems unlikely to me even with my limited understanding of how the game works)
You need to find a condition that increases supply demand, like Frontier or Military bases. (I could only find military bases in that particular file, and I don't know how that event works or where it sits)
Commenting these out should drastically reduce demand, as they seem to be the only ones actively creating demand.
I don't believe NPC fleets actually are considered by the market simulation, especially under considering that Large templar fleets exist, should you use that mod. I don't want to know how many supplies/day a fleet with aforementioned 7 Archbishops would take if it were a player fleet.
Disclaimer: I dont have an actual idea how most of these interactions really work, so this is mostly guesswork.