The reason so few houses are 3 phase is simply cost.
To supply single phase, the POCO needs two primary lines. Either one hot and the neutral, or two hots. There is one transformer. The secondary (from the transformer to the meter) needs to be 3 conductor.
If the service is 3 phase, a minimum of 3 primary lines are needed. If all 3 lines are hots, the service can be either an open delta, a closed delta, or a wye. The open delta needs two transformers, the closed delta and the wye need 3 transformers. The secondary here is 4 wires.
If the service is a delta, the secondary will have a 'high leg'. There will be 240 volts between any two hots, two of the 3 hots will be 120 volts to neutral, the 3rd hot will be 208 to neutral.
If the service is a wye, there will be 208 (not 240) volts between any two hots, and all 3 hots will be 120 volts to neutral.
I would strongly not recommend installing a 3 phase panel in a house that's fed by a delta system. A 3 phase wye would be fine though. The reason being that sooner or later, someone will install a single pole breaker on the high leg, and send 208 volts to a 120 volt device. With obvious results! A single phase panel with a delta breaker (feeding an A/C unit) is fine. The only place the high leg exists here is the 3 phase A/C unit.
A 3 phase delta panel installed in a commercial/industrial building is OK, usually persons installing breakers in these buildings are more experienced, but I've still seen plenty of stuff blown up by the high leg here as well!
The only reason I can think of to install a 3 phase service to a house is because the house is huge, or there is 3 phase equipment that's not practical to run from a phase converter.
Rob