What's defined as genius from the genius of geniuses is that it's the ability to continually lay stones.

To build upon something.
This is different to talent which is inherent ability that someone is born with.

So regardless of whether someone is "talented" or not, everyone has the capacity to cultivate genius.

What sets the casts of human beings apart is the willingness to walk forward despite circumstance and to make use of everything in their way.

Even an ant or worm can become godlike.