You can get the motor but, have to figure out everything else on your own. There other expensive parts. Add the cost of batteries and you might as well buy a new EV.
Yes, the cost is on the high side at the moment. It is impractical, but it may be the only choice we ever have if we do not want an internet connected vehicle.
Internet or some type of electronic identification device will probably be required in the future for insurance, law enforcement or tax collection purposes. It will be embedded in the license plate.