There has been a general rise in battery electric drive train retrofitting in classic cars from 60s and 70s so perhaps we could see Toyota refit 3 or 5 year old gasoline/hybrids with electric powertrains as consumer preferences or emissions regulations change.
While Toyota have the car, they could also update a whole host of things to add value. Interiors and car technology seem to date horribly so getting the latest in car entertainment or driver assistance systems could be another potential revenue stream. Cars also undergo 'mid cycle refresh' so Toyota could do something as simple as bumper updates and swap out newer body parts. Generally the under body remains unchanged in a vehicle lifecycle so swapping out headlights and a bumper would be trivial.
The car industry has for a while been in a existential crisis regarding projections of falling sales and lower revenues. First it was the rise of ride sharing removing the need for personal vehicles, next it was the autonomous driving and now it is electric vehicles with longer service lives and improved reliability. For auto manufacturers, they have been looking for other revenue streams. Recently it has been the growth in services - namely subscription services promising vehicle feature updates and access to 'connected' features. The re-maufacture of vehicles with improved battery packs and the electric drive trains along with other vehicle updates is just another area they could create new revenue streams.