Graham Hancock is very interesting, and you could also check out his latest Netflix series too. Much is speculation but, the obelisk were probably made by basic tools and some ingenious methods.

The ancient Egyptians use to heat the giant obelisks with fire to soften the granite then they used simple tools like a 5 pound round stone to break up the granite that came from the Egyptian Quarrie's. This is how the ancient Egyptians would quarry and cut granite for the obelisks when using simple tools.