The key is PR,business contacts and of course legal barriers.So, It's truth there are too many clones of for example Litecoin and may their market cap be millions of dollars and we also know too many good but dead projects which have not had good pr managers or may they didn't have special goals,The problem isn't only in themselves.despite the fact I always try to take into account the principle : ,,X Coin that is the first tool of its kind will have a strong First-mover advantage''.
Anyway the answer is PR and artificially created problems or influences.