A philosophical roadblock to genealogy?

I was talking to a cousin of mine the other day [it's not hard for a Cajun to do that] and I as usual discussed genealogy. And my cousin said there was a fairly straightforward tack that could dismantle any importance to the concept of drawing any familial conclusions. Basically, it involves transmigration. AS Meat Loaf said, "Life is just a highway, and the soul is just a car." Only here, the soul is the driver, and every fourscore years or so the driver decides to get a trade in. Always for a brand new car. With no memory or paperwork on any previous cars he/she may have owned. And the genealogy I love doing amounts to tracing the production of the auto factory. The soul goes on to drive something new, completely different, by apparently a total random [or at least unknowable to us] system of choice in finding a new car to drive. And so we die, in bodies royal or pauper, with the next model having nothing to do with any previous one, only perhaps in how we drive it. Which means we should try not to have too many accidents lest we lose a Cadillac and wind up with a Citroen or worse, a jalopy. Now this didnt mean a fatal malfunction for my overall thesis on eternity of families. It just meant my genealogy trees may not trace them as well as I thought. My cousin was quick to add that the souls, driving their new cars around, could still well be drawn to seek out drivers they knew in previous races [on the idea that there just had to be a purpose in our going around this track however many times we go]. Causality seems to demand a purpose for everything. God just doesn't play dice with the universe....