Experience matters a lot in this cases. The bitcoins are first and so are more experienced too in the cryptoworld
I think On paper it's easy to say that all coins are similar, but a single line of bad code can be a big disadvantage and experience with bitcoin makes it clear that we will not have big problems easily. To conclude a coin does not really produce anything. Their value is based on trust and usage.
Bitcoin is widely used and this is what makes bitcoin more valuable than other crypto currencies. Bitcoin is better tested at higher volumes and over a longer period of time which makes bitcoin more reliable than other crypto currencies.