That is the only advantage of Bitcoin over other digital currencies, it is the first digital currency. If Bitcoin is not the first digital currency, I don't think that we can still say this. Bitcoin has the highest price but it don't have great features like fast transaction and anonymity like the other crypto currency has. Bitcoin will be just above other currencies in terms of its price.
Would have to strongly disagree there... if you can only see this first-mover advantage, then you perhaps missed out a lot on the whole idea behind Bitcoin, as described subtly in the white paper, as pointed out by many early and current developers, some active on this forum.
Let us forget about price and volume, which is really all that contributes to this market dominance. And which is why even if this "dominance" drops to 5% or less, it will mean little about true dominance - the confidence and preference of its users against any other alternative.
Strip away the cosmetic superiority of altcoin's technology and Bitcoin is still unrivalled in terms of security and robustness. Bitcoin is dominant. And that dominance isn't being regained or lost, it just grows with each day, with each challenge overcome, with each alt propped up as the next pretender.