Fertilizer is not really a positive, as it does not replace carbon (and also destroys micro-nutrients in the soil) - eventually destroying the soil. Grazing animals restore carbon to the soil. The only attraction of petroleum fertilizer is that at least initially it was cheaper than bird guano, grazing animals, etc.
Plastics are a positive IF properly disposed of in a system that ultimately incinerates them in a trash to power plant or equivalent. Land-filling plastics creates large scale micro-plastic contamination of the environment.
Concrete and steel - oorah!