>>75599
From looking here:
https://gitgud.io/pregmodfan/fc-pregmod/-/blob/pregmod-master/src/js/economyJS.js
Ctrl+F'ing "SectorCounts" and reading from there on until it starts talking about agent bonus, my understanding is that your prosperity cap is 10 times the number of sectors in your arcology, with the Penthouse, Brothel, Club, Arena, Arcade, Dairy, Farmyard, Barracks and any Dense Apartments not counting, regular Apartments counting for only 5 points each, and the Transport Hub counting for 15 points instead. This means 10 points per Luxury Apartment, regular Shops sectors, FS-related Shops, Market sectors, the Corporate Market, Manufacturing sectors, Pens, Sweatshops, and and the Weapons Manufactory.
On top of this the security drones, water reclamation, solar apron, power transmission lines and spire upgrades further up the cap up to 150 points, 10 points if only the drones have been installed, 30 for the drones plus the water system, etc. Note that in most arcologies the spire adds 4 Luxury Apartment sectors, which further raise the cap by 40 points on their own.
The thing is that this would suggest that my late game, maxed out Urban arcology would have a cap of 410 prosperity (31 total sectors other than the Penthouse, minus 5 because I have the Brothel, the Club, the Arena, the Dairy and the Farmyard (for food, it's for food, I have it for food) makes 26, times 10 is 260, plus 150 makes 410) but its actual prosperity is 360 and considered maxed out at that level. From some experimenting in Debug mode in other arcologies, it seems that the spire upgrade doesn't actually raise the cap beyond the benefit the 4 extra Luxury Apartment sectors bring, with the uh... Tower arcology gaining no apparent benefit from its fountain (I considered that maybe the 50 extra points from the spire were only for the Tower arcology to balance out it having fewer sectors but apparently no). I would love to be corrected if somebody knows something I missed here. My guess is that the data for most of the upgrades being in src/arcologyBuilding/ManageArcology.js but the spire being in src/arcologyBuilding/presets.js might have something to do with it.
In any case you should build those upgrades as you reach the prosperity cap, except the spire if you have the Tower arcology because that one is only for show. Some of the specialized sectors in the arcology lower the maximum prosperity but that seems like a minor price to pay for the other benefits they bring, just don't build a Dairy (or whatever) if you are going to leave it empty. Urban arcologies (31 sectors other than the Penthouse) have a higher ceiling than Offshore (30), Oceanic (29), Ravine (29), Rural (28) or Tower (26) ones. You should turn all your Apartment sectors to Luxury Apartments if you want max prosperity, or to Dense Apartments if you want more lower class population, which would also bring more people of the other classes MAYBE leading to a larger population (including rich population) than if you had prosperity-maxxed with the Luxury Apartments. There seems to be no good reason to have regular Apartments other than you haven't gotten around to upgrading them to one of the other two types yet, since the Luxury ones are always better and the Dense ones provide a different benefit (which may also be better).