The high price of bitcoins is a giant disincentive for the network to prevail, because it raises the cost of using the network to confirm transactions. (i.e., miners are being paid huge amounts of money, because BTC are so valuable) The major financial institutions will want an opportunity to mine a large percentage of whatever cryptocurrency will take off as the dominant paradigm. Imagine how easily banks like Wells Fargo could create financial incentives for merchants to take their bank-backed crypto-currencies instead of BTC.
It's not the high price that is the disincentive, instead of the bitcoin we can use the mBTC or uBTC, it is the volatility that it is the problem.
Here, the Bitcoin protocol can and has been cloned to allow for alternative coins. It way well continue to be the dominant model for how coins should be tracked. But that doesn't mean that the original denomination will remain relevant. The barriers to entry for alternative coins are just too low. So far, those coins have mostly been weak imitations. But the launch of a GoogleCoin or BOACoin could instantly change that and create a crisis of confidence in BTC.
I agree with the last paragraph, but only a little, the more time passes, the more unlikely it is that a new coin can easily takeover, even by a big player and even if the coin is technologically advanced or better in some way. This is simply because of the infrastructure and ecosystem in place for the bitcoin. Products and services are being developed around the bitcoin and newer coins dont have that (yet) it is increasingly difficults for new coins to compete.