It would make no sense to leave the engine if it is no longer operable - that's a lot of weight, and a lot of space.
In the A3 e-tron (and the related Golf GTE and Passat GTE) the electric motor is integrated into the 6-speed automatic transmission, so you would be stuck keeping the weight and complexity of that transmission.
This vehicle has one of the smallest batteries among PHEVs (8.8 kWh), so the range with only the battery is very short; a Chevrolet Volt or Mitsubishi Outlander PHEV could be usable without the engine and with only the original battery, but the A3 e-tron would need much more battery.
PHEVs are uncommon and expensive enough that they seem like poor targets for conversion to a less functional type of vehicle, although I suppose it might make sense if the engine died and was too expensive to fix or replace.
In the A3 e-tron (and the related Golf GTE and Passat GTE) the electric motor is integrated into the 6-speed automatic transmission, so you would be stuck keeping the weight and complexity of that transmission.
This vehicle has one of the smallest batteries among PHEVs (8.8 kWh), so the range with only the battery is very short; a Chevrolet Volt or Mitsubishi Outlander PHEV could be usable without the engine and with only the original battery, but the A3 e-tron would need much more battery.
PHEVs are uncommon and expensive enough that they seem like poor targets for conversion to a less functional type of vehicle, although I suppose it might make sense if the engine died and was too expensive to fix or replace.