> I don't think I've had a truly original idea in my life.

There’s no such thing as a truly original idea. It is all just combining A+B!

Sometimes you generalize A into A'.

But often results are incremental and obvious.

But also if you jumped from A to A''''', nobody would understand why or what it relates to.

if someone did have a truly original idea, then everyone would probably think it was terrible anyway and we'd all ridicule them, because we'd have no frame of reference for X + Y if all we know is A and B :)

Cavemen came up with the initial A & B, and we’ve gone from there? (Didn’t think this through much yet!)

Cavemen invented language, language isn't just combination of concepts, it requires defining all the concepts.