Yes and no in my opinion.
Yes, we can have other crypto-currencies, but they would have to be small niche.
No, we cannot have another widely used global crypto-currency that competes with bitcion. The network effect of bitcoin is so powerful that anything technically superior would simply be adopted into bitcoin.
The fact that bitcoin is open-source is precisely what makes me so bullish on it, because it gets better with age
Yes Bitcoin evolves, but since it is such an important thing insofar as a lot of people have a lot riding on it, progress is necessarily slow and careful. The BIP 16/17 issues illustrate this. There are also a lot of architectural decisions that are very deeply baked into the cake at this point.
This reality has both pros and cons. More pros than cons in my opinion, but it does nobody any good to paint over and ignore what cons there are.
