The barrier to entry is low. The barrier to mass adoption is high. Bitcoin is winning that war handily compared to any other cryptocurrency. There are definitely flaws with Bitcoin that will need to be ironed out, but the world's most elegant cryptocurrency is useless if no one has heard of it or uses it. First mover and marketing often trumps technological advantage. A non-techie doesn't care about Ethereum or Monero, but they do care about Bitcoin when the news is talking about how valuable it is everyday. Bitcoin is changing the mindset of what money is to the masses, this can't be said for other cryptocurrencies.
Perhaps Bitcoin will fail at some point in the distant future, but for the time being it is absolutely the most influential cryptocurrency, this can easily be seen by all altcoins' value being pegged to their BTC conversion rate.