You beat me to it. Visually it was a great movie, but I never understood what the point was, or even if there was a point.
Saw it the day it came out!
Been scratching my head, (among other things) every since! 8)
When I was a kid, I was blown away by the film. I really didn’t care about the logical plot.
Read the book.
.
We see the monkeys (humans) struggling and on the verge of dieing off. The obelisk appears and suddenly the apes discover tools. (the obelisk is placed there be a superior race or being) skip forward 3 million years. Think of it as a 3 million year evolution timer, when your apes can get to the moon they are ready to make contact with. Man goes to the moon and finds another obelisk. When it is dug up a loud shriek is heard, it is a signal that is directed out toward Jupiter.
The mount a mission to find where that signal was sent to. and go to Jupiter where a third obelisk is found. It is a portal of some kind. Bowman goes in and is transported somewhere. He spends some time in what look like a hotel room where he is transformed, and returns to earth as a baby. But as a baby of the advnaced beings. Sent back to earth to watch over it.