Yes, every car has this capability, I had a 45 amp power pole connection in the back of my Prius feeding an ISOpwr with an aux battery for ignition off usage of just the radio. This served a bonus purpose in the Prius with the undersized 12V battery, I could jump start my self by disconnecting those two from the ISOpwr and plugging them into each other.
This was simplified in the Prius by the 12 V battery and the DC-DC converter were both in the rear of the vehicle. I was sad to see the Bolt's 12V battery under the hood. I haven't gotten around to doing the same in my Bolt yet, mostly as I haven't decided on an antenna mount I'm happy with.
As an aside, on the Puerto Rico thing, 50 hams will be departing in the next couple of days to deploy in teams of two at shelters across the island. Their kits include HF digital and SSB capabilities as well as VHF. They are also self sufficient power wise with batteries and solar or their own generator for recharging. Primary mission is supporting shelter communications with the outside both within the island, supplies and emergency services requests, for example, as well as with the mainland by sending shelter rosters to the mainland via Winlink for entry into the Red Cross tracking system and the like.