Lindy Effect – Bitcoin is the oldest cryptocurrency.
Tyranny of the Intolerant Minority – Bitcoin Maximalists will use Bitcoin but no other altcoins whereas Altcoiners will use both altcoins and Bitcoin.
Network Effects – Bitcoin has the most developers and users by far.
Illegibility – Bitcoin, while not being “elegant” (synonym for legible), is the simplest system that works. From that, complexity can be added on top according to the needs of the community.