some choose not to have children or are celibate so I wonder how we arrived to this point.
Those are specimens, not species, operating under modern conditions. If you were a cavewoman living 15,000 years ago, it seems exceptionally unlikely that you'd have any choice at all about bearing children or not.
if you what you say is true, we've far exceeded our purpose.
How? We continue to procreate. Population continues to rise. It's about, at a primal level, control of resources. You're saying purpose and adding in an unspoken "destination" rather than a species wide goal. THink of it like a sports team. If you are a basketball team and injuries were never a concern, would you ever decide you'd won enough games? Do you think the UCLA Bruins, of the 88 game win streak, decided in game 89 "enough winning?" THey have a goal, every day, to win the game, just like living things ultimate goal is to reproduce, as much as possible. You seem to be thinking of it in terms of someplace every species wants to "arrive" at. It's not the same thing, though it might be a subtle distinction. Does that make sense?
Our advancements seem to have no real or practical purpose and is far beyond any need to procreate and yet here we are.
Which advancements are you talking about specifically? The important ones, like medicine, which gives us years and years more reproductive opportunity potential? Which made childbirth a far less dangerous proposition? Large scale farming which makes food more available?
Humans teach strangers, non genetic linked others to survive and thrive. I can't think of any other animal that does that as well.
Why do antelopes move is such massive herds? They're not all genetically linked, at least not directly, but they all have an interest in making sure the maximum number of antelopes survive. Monkeys adopt orphaned monkeys on occasion. Elephants have sophisticated societal markers. Why? To ensure the maximum depth of their genetic pool, perhaps. This sort of altruism exists in the animal kingdom all over the place. It's not as explicit as with humans, but it's there.
An alpha predator isn't looking to be more alpha because the only competition they have is with each other generally speaking.
You lost me here. Are you talking about APEX predators, or ALPHA Male / Female specimens? The latter is an alpha because they compete and make others subjugated. The former never stops trying to control more and more resources. WE're an apex predator.