There is no Hierarchy of upgrade dependency currently. I can build anything I wish first, however logically, a Base Station is the beginning of the colony, the base station may require “power” from the power production upgrade in order to sustain life. Transport requires “Power” to keep the transports charged up and ready to use for mining. Robot Assembly is required for building and maintaining transports.
Could add a research facility as an upgrade to allow scientists to research advanced technologies. This would open the door to skillsets required for NFT citizens. Create a dependency between land owner and citizens. Maybe expand on the building types, facilities, “Solar Power Station”, “Wind Power Station”, “Nuclear Power Station”. Reconfigure current naming schemes to “Basic Robot Assembly”, “Basic Transport”, “Basic Power Production”.
Creating dependencies creates a required upgrade path in order to achieve certain levels of production. Creating citizen NFTs with skillsets such as Scientist, Farmer, Miner, Medic/Doctor, could create an ecosystem for NFTs. Something to consider and maybe add to the ecosystem to create demand.