To produce more power, you need to draw more voltage or amperage. Like Sam mentioned, wall sockets are normally limited to 15 amps and you are stuck with 110v AC. My sub amp is on a 20amp dedicated circuit with larger wire running to the outlet. Guys on other forums have installed 220v outlets for amps in the 4,000w range.
The current trend for car amps is basically no limiters on their design. Look at the sub amps especially.
@ Max Power 13.8 VDC – 1 OHM: 9595W RMS
@ Max Power 13.8 VDC – 2 ohms: 6305W RMS
@ Max Power 13.8 VDC – 4 ohms: 3646W RMS
@ Max Power 12.6 VDC – 1 OHM: 8000W RMS
@ Max Power 12.6 VDC – 2 ohms: 5256W RMS
@ Max Power 12.6 VDC – 4 ohms: 3040W RMS
See the jump in power from a 1 volt increase in the charging system. If that amp is stable to 16v then it would really push the power. But one spec that is very, very important - Consumption Maximum Music @ 12.6 VDC: 431 Amp. That's right 431 amps of power. On a compact car, the alternator puts out about 120amps with about 75 to 85 used to power the car and accessories like A/C. That leaves 40 to 50 amps to charge the battery and power the audio system. Pull more than that and you have headlights dimming and soon a dead battery. In the home environment, you can't pull more than the rated amperage or you throw a breaker.
So why don't home systems use low impedance speakers? There's no use in doing so. And with most manufacturers sticking with 8 ohms, it makes compatibility easier.