Decentralization in general is less efficient and therefore requires more resources. For example small scale farming has less yield per acre compared to large scale farming, thus you have to use more acres to produce the same yield leading to more environmental destruction. Or with the small local workshops, each of those workshops will require a vast array of machines and tools to handle every situation, some that may be rarely used if at all, so you need to produce thousands of copies of these tools for every shop that may not be used, using more resources, as opposed to having to only create one copy for a central repair facility.

The cost, including the environmental cost, of transport rarely exceeds the gains in efficiency from centralization. Working at an office for a computer job is the exception as theres very little gain. But working from home in a job where you cant send your work over a wire to the next worker would obviously lose a lot of efficiency from work from home.

We don't want to spread people out, the more spread out they are the longer it will take to get places and the more likely they will use a car. We need people in dense centralized places because that's where we get these efficiencies of scale. Public transportation becomes better with density, distribution of goods becomes easier, heating and cooling large complexes is more efficient than individual homes.