Karl Marx is without doubt the most influential and well-known of the Young Hegelians, closely followed by his BFF Friedrich Engels. Max Stirner (pseudonym of Johann Kaspar Schmidt) is a relatively obscure proto-anarchist Young Hegelian (holding very different views from the rest of the gang) who today is mostly known by the few people who care to research anarchist history or those who have read Marx's/Engel's The German Ideology, which attacks Stirner's ideas.
What if Marx's and Stirner's fortunes had been reversed? What if Stirner's The Ego and Its Own had become one of the most widely read works in history while The Communist Manifesto gathers dust on university library bookshelfs? What would be the effects on politics, the revolutionary/non-revolutionary left and academia during the 19th, 20th and 21st centuries? Could Stirnerian anarchism become the dominant "left-wing" ideology, or would a more collectivist, "proletariat"-focused socialism inevitably rise and outgrow all other ideologies? Anarchists IOTL seem to come in two flavors, idealistic intellectuals and angry teenagers. Could anarchism, especially individualist anarchism, ever become a mass movement?