Don't know. I may have decided not to care too much about this. It won't happen in my lifetime so why should I care.What do you anticipate the future “best of the best” will be? Nietzsche's Ubermensch? *
All life must feed on other life. The more powerful individuals get, globally, the larger the amount of force that must be mustered and applied in order to better one's opponents. This is the core problem of any entity that has sufficient power to destroy all of its kind. Until we turn away from paying heed to centralised power, until enlightenment becomes a substantially more frequent desire than power and possessions, then regardless of the capabilities of those who rise to the top of the herd, we are a Dead Species Walking.
Doesn't matter though, as in the big scheme of things - and as all our descendants are not actually us - the universe is big enough for some other life form to achieve something close to immortality - but then even they would self destruct, most probably by devolution. When entities create tools for survival, they will gradually lose what they don't use, they physically soften, and such entities will become subservient to the successful workings of machinery which over sufficient time a key component must fail.
I still prefer his maxims to Thus Spoke Zeddie.*I read about a third of his book, but it was a little much for me right now. However, the overman was clearly defined.