Opening words: I'm a dreadfully inferior being, and so are you, dear reader, when stood next to the genetically engineered humans of the future.

That said. Strap yourselves in for some crazy talk...

I think we could probably safely organize a Ship Of Theseus scenario, to migrate humanity into a future where the gene pool gets better and better, with each successive generation of children, so long as two things hold
true:

1. We don't solve for immortality in a way that forces us twentieth century descendants to burden the genetically engineered betters.

2. A system of machines of loving grace watch over the lot of us, to see to it that we all live in a yellow submarine. That is, we strike a chord that rings in a stable, reasonable world peace of sorts.

Long shots, but I think it could be done. The first part takes shape whether we achieve ultra longevity or not.

Genetic super people are going to show up, and in a hundred years there will be a lot of them. They be smart. They won't be interested in any kind of stifling hang ups we insist on carrying forward into the future. That said, I surmise they'll be mostly gracious and reasonable, even if a bit inflexible yet fair. This is usually symptomatic of intelligent people with met needs. So they'll probably solve a lot of problems for themselves, not get in the way, and excel in life, no matter what's fair.

With ultra longevity in the picture, we'll look stupid next to geniuses, but they'll have to live with us like insufferable racist grandparents rendered mostly harmless by the frailty of our lesser bodies built upon natural genes and yesteryear's diet and lifestyle. Mostly. We probably won't be much of a threat, face to face, on the street.

That said, power and influence of large mobs is still relevant, and nuclear weapons and other spectres of 20th century global conflict will still pose credible threats.

So, the machines. How can the machines change things? Well, if we manage to automate most drudgery, holding down a day job would be superfluous. Meanwhile, our internet arts and crafts and musical stylings will be like kindergarten scribbles hung up on the refridgerator. For the most part they already are, but it should become possible to lead loves of stimulating leisure, far and wide, so long as no one freaks out about it with economic holy wars of reputation and status. Ample distribution in a world of mostly efficient recycling is close enough to taste, if we automate all the things, and no one has to lift a finger. There really hasn't been a prticularly novel invention one store shelves that wasn't a miniaturized elite version of something that existed in 1970. So food and possessions are kind of a solved problem, damn near.

So, whether we're really immortal, whether we enjoy longevity or not, us lesser being should be capable of dying off peacefully by attrition. With enough to go around, patience will probably hold up, and over time, our genetically alter descendents will evolve at the geological light speed of the birth rate, and in less than another thousand years, maybe we'll still be around, and maybe not, but I think it's possible for everyone to squeeze into this elevator, and get off at whichever floor they want, if need be.

I don't feel much panic in the evolutionary sense. Just so long as the machines are kept at bay.