The fixed costs of owning two cars means that it rarely works out. Rental cars can work, but again the math rarely works out because it is so expensive to rent a large car.
It may not be viable to maintain a large fleet of family-vacation-type vehicles just to satisfy the demand for summer holidays in August and ski trips in February.
This is merely an interstitial time until you can run from Bucharest to Leipzig with fast charge stations in every town and village along the route.