Good points. I haven't always looked at discovery and invention as two totally unrelated issues. I believe a lot of humans got their ideas obviously from what is already occurring in nature all around them.
As an example, how about a good chunk breaks off a obsidian cliff type structure, leaving a large precise flat segment that is left on the cliff or laying on the ground that reflects onto a spot and fries a plant or animal. A person may see this and observe the bright light is coming from that flat source. Maybe they get fire. Maybe they start fooling around with the bright spot and experiment by throwing things in. Maybe they throw in Bob and have the first sacrifice to the sun god. Who knows.