>>18061621 (OP)
>Why didn't his beliefs manifest itself in a movement?
Stirner's ideas are fundamentally anti-movement, because belonging to one would mean submitting your ego to something larger. You could technically still have a movement of stirnerians, but, generally speaking, it's hard to build a movement out of pure selfishness, because man is naturally enclined to seek justification in what he does, rather than pure egoist reason.
>Why did Marx get popular instead?
Because Marx gives a material account for alienation that Stirner doesn't. Stirner essentially says that man is alienated through morals, the state etc. This might be true, but it fails to correctly determine the cause and the underlining character of these and instead treats them as ad-hoc irrational things when the issue is deeper and multifaceted.
The other point is that Marx also formulated a constructive critique of the economy alongside his alienation. This gives a material basis for his followers to cling on rather than vague philosophical notions. In fact, most marxists have a hard time understanding what alienation is, but still understand that it's apparently caused by the bourgeois.
