Well I suppose that's possible, though I think it's a moot point. Sibelius was super-critical of his own work and was known to have bonfired some of his later music. Rossini virtually stopped composing when he reached 40 and lived the good life of a gourmand for the rest of his days, which were many (reflected by his ever-burgeoning waistline). I suppose that if you're well enough off and you consider that your music can't evolve any more, you might be tempted to simply retire. As for the booze, Beethoven had cirrhosis of the liver when he died and was known to be very fond of white wine, but he composed right to the last, producing arguably his greatest works in his last five or six years. So who knows.