We use 110 to charge our PHEV (which admittedly has a very small battery). I would like to get a PHEV for our next vehicle, but the price premium makes it very unattractive for us. Some vehicles are $12k more for PHEV, and given how little we drive it would never be worth it. It's nice not tanking up often, but the extra cost (and extra car insurance) isn't worth it for us.

Outlets are standardized and not specific to EVs. If you mean the charge plug, that's different.

Assuming you're in the US/Canada or other country with 100-120v service, a standard wall socket is sufficient for many full EV users and plenty enough for a PHEV which has a much smaller battery. Think about how much time your car spends sitting in your driveway/garage...and if you don't get a full charge, so what? The engine kicks in.

The wiring gauge is good for a certain current. That affects what sort of plug is installed in the wall, as they're keyed according to current limits. The EVSE can be programmed to not exceed the appropriate current, which is 80% of the breaker's rating.

If it was wired for an EV, it's almost certainly not 100-120v but 208 or higher, in which case even if it's a 15A circuit, that's definitely enough for a PHEV and sufficient for charging all but the largest EVs practically overnight.

A 208v, 15A circuit is good for 2.5kW. If you get home at 7PM and go to work at 7AM, you'll be able to charge 25kWhr each night, roughly. Average EV efficiency is about .35kWh/mile, so that's sufficient for 70 miles of driving.

You'll probably have 240V in North America in a residential detached/duplex/row home. It's low/high-rise apartment buildings/condominiums where you'll see 208V.