Twentieth Century Music's Greatest Tragedies

For me, the most unremitting losses dealt the world of music in the twentieth century were the tragically early deaths of three performers who, at the time of their passings, were already legendary in attainment and promise.
I have already written about the American pianist, William Kapell, who was killed in a plane crash at the age of thirty one. The few recordings left to us are vivid descriptions of a massive pianistic and intellectual entity, rivaled by only a few great pianists many years his senior.
Guido Cantelli was also killed in a crash, he at age thirty six, and at the time of his death was already considered a conductor on the very edge of a meteoric career. Arturo Toscanini, the legendary conductor, described Cantelli as the most impressively gifted young musician he had ever met (do be reminded that Toscanini's son-in-law was Vladimir Horowitz), and he was never told of Cantelli's tragic end, which he survived by only a few months.
The Rumanian pianist Dinu Lipatti died in his thirty third year of a blood cancer, and had already achieved a status essentially equal in musical probity and eclectic powers to his world -renown contemporaries, a truly amazing status to have arrived at so early in a career.
Where would these three giants have taken us, had they lived on?