For those who don't know, the term white elephant refers to anything that has only imaginary or perhaps aesthetic value for the owner, but has no practical or functional value. When applied to any Japanese used car for sale, it seems to merit quite some thought.
To answer the question, one possible answer a collector of used Japanese cars might give is: no, my used Japanese cars still have practical and/or functional value. How so? Well, perhaps this car collector is still able to get some mileage out of his Japanese used cars. Perhaps on weekends, he brings one of his Japanese used cars out of his garage and takes his family out for a trip to church, or on a picnic to a nearby park, or even a bit further away to a beach for an afternoon of water-based activities. For such a person, his used Japanese cars would not be white elephants in the strictest sense of the use of the term because the vehicles can still be used though perhaps not as regularly as newer cars.
Another answer a collector of used Japanese cars would give would be the opposite: yes, my used Japanese cars are actually white elephants, in the sense that I do not derive any practical or functional value out of them. Many used cars are gas guzzlers, because their engines are not as efficient at burning fuel as when the cars were new. Others have deficiencies in car design that make them too bulky and too large for fuel efficiency.
If you spend an inordinate amount of money upgrading, renovating and taking care of your used Japanese cars, perhaps you need to examine your reasons for owning such vehicles in the first place. If you just like to look at them once in awhile (when you have leisure time on your hands), then leave them locked away for months on end, then perhaps you may need to ask yourself whether that is enough reason to hold on to your collection.
Some people go to great lengths to preserve the quality of their cars (regardless of what country made them) because they want to be able to use them for a long time. Then they sell their cars because they need to upgrade their mode of transportation to more efficient and less troublesome cars of newer make. In that sense, cars would not be white elephants because they do serve practical and functional purposes for the owners while they can still run. But what happens when your used Japanese cars completely die on you, meaning their engines go kaput with no hope of being fixed anymore? That is a fate that all vehicles (and their owners) have to face eventually.
In that case, the only real value your used Japanese cars would have would be if they were sold for scrap, or as spare parts for other used Japanese cars. If you seem to have become emotionally attached to your car, it may take time though before you can let go - but all of us have to let go of our material possessions at some point. Some just do a better job earlier than others.