It’s unfortunate and inconvenient. However A transfer switch requires <3 minutes to engage. If a car was able to supply 30-50 amp via compatible plug it would work reasonably well even absent unified v2h standard.

Most recent teslas support 20amp at 120v output via official $100 cable adapter. Some other cars support about 20amps too, eg RivianR2. While it falls short of desirable amperage the car manufactures can bridge the gap if they wanted to. Even now I can run the bare minimum of workloads - a full size fridge, a small AC or Microwave, LED lights, and phone chargers.