Thomas Malthus' prediction of mass starvation resulting from diminishing marginal returns has NOT been fulfilled because

a) Malthus ignored other factors like technological change.

Explanation:

Thomas Malthus (1766-1834) was an English cleric and a scholar, most known for his demographics theory. He is an author of An Essay on the Principle of Population, where he observed that increasing production of food resulted in improved well-being of the population, but this was temporary because it led to a population growth. Larger population led to the restoration of original production per capita.

He was mainly wrong because he did not account for improvement in technology of production. Development and widespread use of technology meant that it is not needed to use the same amount of energy to produce goods. Production increased much faster than the increase of population, which resulted in a failure of his theory.