Two points: First, the OP claimed "Does he finish what he starts? Geniuses almost never do." but gave no evidence. Second, on finishing, we can consider I.

Two points: First, the OP claimed "Does he finish what he starts? Geniuses almost never do." but gave no evidence. Second, on finishing, we can consider I. Newton, W. Mozart, C. Darwin ('Origin of the Species'), R. Wagner (operas, especially 'The Ring'), J. Maxwell (E&M), A. Einstein (general relativity), J. Oppenheimer (A-bomb), S. Ulam (H-bomb), J. Salk (polio vaccine), D. Henderson (Smallpox eradication), J. Heifetz (violin), W. Gates (Microsoft), A. Wiles (Fermat's last theorem), J. Bezos (Amazon).