If you live in a subdivision built within the past couple decades, your electric runs underground, making it quite expensive to run a second or third primary phase. You also then need a three-phase transformer, which is considerably larger than a typical one-phase. Oh, and your service will be commercial/industrial, which typically comes with demand and energy charges that can be quite steep: https://www.northwesternenergy.com/docs/default-source/docum...
That's true, for North America, but entirely misses the point I made (i.e. when you try to push dozens of kW into a house, single phase becomes worse than a below-average idea).
